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The unprecedented emission reductions during the COVID-19 lockdowns in 2020 provided a natural experiment to elucidate aerosol–radiation-cloud interactions and their effect on convective weather phenomena, particularly thunderstorm occurrence and lightning flash rate density (FRD), across the Indian subcontinent. The significant reduction in anthropogenic aerosol emissions, especially across the most polluted Indo-Gangetic Plain, led to a marked decrease in aerosol optical depth (AOD), altering regional cloud-aerosol interactions and radiative effects. A rise in ENSO-compensated lightning FRD and an increase in thunderstorm days (TDs) were associated with aerosol depletion, suggesting a favorable environment for convective initiation under relatively cleaner atmospheric conditions over the extremely polluted region. The reduced AOD likely led to enhanced surface heating and decreased upper-level warming, reversing the previously stable stratification caused by very high aerosol loading. This natural instability favored the formation of a greater number of widespread thunderstorms. However, the observed reduction in lightning FRD per TD during the pandemic year indicates that, while more storms formed, each storm exhibited lower electrification, likely due to diminished cloud condensation nuclei. Relatively lower aerosol concentrations can promote an increase in storm frequency through radiative destabilization of the atmosphere. However, these relatively cleaner conditions also tend to reduce lightning frequency within individual storms, as the limited presence of aerosols constrains non-inductive charging processes in clouds. Thus, environments with fewer aerosols are associated with more frequent storm development but a decrease in lightning flashes per storm, reflecting a complex interplay between atmospheric composition and convective electrification. These insights advance understanding of convective storm responses to aerosol variability and have important implications for future atmospheric electrification trends under changing emission scenarios. This dual effect highlights the complexity of aerosol–cloud-precipitation-electrification interactions. It has implications for understanding convective weather responses to air quality changes and future climate scenarios driven by aerosol management strategies.

Six cases of dust storms that occurred over the northwestern and northern parts of India have been studied here to understand the effect of dust on the lightning characteristics of these storms. Satellite pictures show high dust content on all six storm days, and ground station data show that visibility was reduced to less than 500 m. Lightning data observed by the lightning detection network indicate that these six cases of convective dust storms produced more than 30 percent of positive CG lightning in the total CG lighting, which is considered to be very high compared to ordinary thunderstorms. Further, analysis indicates that the current carried by positive lightning is much higher than negative lightning. In some cases, the lightning flash rate reached more than 200 flashes per min (fpm). Observation shows that all these thunderstorms were accompanied by dust, and hence, incursion of the abundance of dust particles into the cloud was likely to be very high. Many earlier observations have suggested that aerosols can affect thunderstorms’ microphysical (such as vertical distribution of the hydrometers) and electrical characteristics. With the abundance of dust particles in the cloud and increased positive CG discharges, it has been proposed that increased dust particles can modify the vertical distribution of ice particles inside a thundercloud and affect the lightning flash rate as well as polarity.

Four years of Indian Institute of Tropical Meteorology lightning location network lightning observation data are used to determine the seasonal and spatial (over different geographical locations) distribution of the ratio of intra‐cloud (IC) lightning to cloud‐to‐ground (CG) lightning in thunderstorms over the Indian subcontinent. The ratio is high (6–10) in the northwestern parts and low (0.5–3.5) in the northeastern parts. No prominent latitudinal variation of the IC to CG ratio exists, but a climatological seasonal variability exists over all regions. In the pre‐monsoon season (March–May), the mean ratio is observed to be 3.81 with a standard deviation of 0.79, and during the monsoon season (June–September), a value of 3.04 with a standard deviation of 0.50. Although convective available potential energy is the regulating factor, little dependency has been found between the ratio of IC to CG lightning (IC:CG ratio) and the total flash rate (f), as well as with cold cloud depths. The ratio is observed to be proportional to the total flash rate as f0.61. The cold cloud depth is most prominently linked with the regional and seasonal IC:CG ratio. The implication of these observed results has the importance of separating CG lightning flash from total and can be used in numerical models to give a proper prediction of CG lightning in hazard mitigation. Plain Language Summary Pre‐monsoon thunderstorms exhibit more intra‐cloud (IC) discharge than monsoonal thunderstorms; hence, the IC:cloud‐to‐ground (CG) ratio is also high in pre‐monsoon. In this paper, we have shown that CG lightning is approximately 20% of total lightning in pre‐monsoon whereas 25% of total lightning in monsoon all over the Indian region. A stronger vertical updraft associated with high convective available potential energy enhances the cold cloud depth. It may expand the mixed phase region, which can broaden and uplift the size of the upper positive charge center inside a thunderstorm. In contrast, the middle negative charge center remains at the same temperature level. Therefore, this process may enhance IC discharge between the upper positive charge center and the middle negative charge center, increasing the IC:CG ratio of a thunderstorm. Key Points The mean intra‐cloud:cloud‐to‐ground (IC:CG) ratio remains high in the Pre‐monsoon season compared to the Monsoon season over the Indian land mass The high cold cloud depth associated with stronger updrafts expand the mixed‐phase region and increases the IC flash rate and IC:CG ratio High flash rate associated with high IC flash occurrences is also responsible for a high IC:CG ratio

Three major sequential widespread dust events were experienced in the northern parts of India in May 2018. A significant impact of these pre-monsoon dust storms on the aerosol characteristics over the Indian National capital region (NCR) has been studied using remotely sensed ceilometer and ground-based measurements at Indira Gandhi International airport, New Delhi, India. The results show that after each dust activity, the significant inclusion of dust aerosols loaded in the free troposphere. Consequently, the direct impact on the lower atmospheric parameters like increase in daily average temperature (by 4–5 K), stepped up (stepped down) diurnal cycles of longwave fluxes (shortwave fluxes), has been recorded within 15 days of dust span. Mainly, the adverse meteorological and radiation features noticed before the first dust storm (DS1), which pinpoints the sudden dust intrusion over NCR, Delhi. However, this dust storm has extensively impacted on the atmospheric vertical dust loading, surface boundary layer mechanisms, and socioeconomic way. Therefore, the detailed analysis of vertical dust distribution and its interaction with mid-tropospheric processes has been carried by using the vertical normalized attenuated backscatter coefficients accompanying the radiosonde observation. The aloft floating dust layer up to 3–4 km has been noticed even after shallow rainfall and persisted at almost the same height for the next 34 h due to low-level clouds. Meanwhile, the sub-dust layer below 1 km is formed due to local activity, which also sustains for a long time.

Introduction Impacted mandibular third molar (IMTM) extraction, is the most commonly performed surgical procedure in oral and maxillofacial surgery, which may present with post-op complications like Inferior Alveolar neurosensory deficit (IANSD). Risk factor assessment by correlating pre-op OPG, CBCT findings with intra-op parameters provides a comprehensive tool for predicting nerve injury which forms the basis of this clinico-radiological study. Materials and Method Hundred patients with IMTM taken up for transalveolar extraction secondary to varied etiologies, were evaluated for post-op IANSD while comparing pre-op OPG and CBCT association with Intra-op parameters like hemorrhage, odontectomy, bone removal and physical observation of the canal. Affected patients on the 7th day were then followed up for 14th day, 01 month and 6 months for evaluating resolution of neurosensory deficit. Results A total of n  = 9 out of 100 patients presented with post-surgical IANSD. Pre-op OPG findings of loss of white lines, deflection of roots and CBCT findings of inferior and lingual canal position were predominant attributable factors ( p  = 0.017). Intra-operatively, hemorrhage ( p  = 0.001), bone removal ( p  = 0.016) and odontectomy ( p  = 0.427) were associated with deficit in decreasing order while canal observation was definitely associated with IANSD ( p  = 0.007). All the patients recovered at 06 month follow up depicting only transient neurosensory deficit in our study sample. Conclusion Varied anatomic orientation of IMTM and its intimate association with IANC may pose as an indicator of post-op IANSD causing both surgeon and patient dissatisfaction. It is, thus, important to assess tooth and canal complex thoroughly and educate the patients about possible IANSD complication after correlating them with intra-op findings to avoid undue clinical surprises.

A detailed study of cloud-to-ground (CG) and intra-cloud (IC) lightning over southern India was conducted using new high-resolution gridded data generated from the IITM Lightning Location Network in southern India (8°–13.6°N and 74.5°–80.5°E) during 2019–2021 period. More than 5.3 million lightning strikes were observed during the period in the region. Peak CG activity is seen in a lightning hotspot located in the midland and foothills of the Western Ghats in Kerala and another CG peak is seen over the Kochi coastal belt (75.8°–76.2°E and 9.7°–10.4°N) in the Lakshadweep Sea. Our study shows that peak lightning currents during the pre-monsoon (March–May) season are mainly positive, whereas most of the currents were negative in the post-monsoon (October–December) season. This shows that the storm charge structures are different in both lightning seasons. Diurnal changes indicate that the lightning in the southern lightning hotspot region is primarily influenced by solar heating and the lightning activity peaking at 15–18 hours (local time). Higher IC activity is associated with pre-monsoon taller tropical cumulonimbus clouds (Cb), and IC activity peaks at altitudes between 10 and 18 km. It is observed that the average lightning activity duration (first to last strike) is 1.8 hours in the lightning hotspot region. Analysis of CG controlling factors shows that, over land regions, strong connections are observed with lightning and thermodynamic parameters like convective available potential energy (CAPE). However, convective inhibition (CIN) shows a weak positive correlation with lightning over oceanic regions. Also, a significant correlation (0.01 level) was observed between sensible heat flux in the lightning hotspot and coastal regions. In addition, aerosol optical depth (AOD) shows a significant correlation with lightning over the central region in southern India.

Purpose: Pediatric cataract is a major cause of preventable childhood blindness worldwide. Although genetic mutations or infections have been described in patients, the mechanistic basis of human cataract development remains poorly understood. Therefore, gene expression of structural, developmental, profibrotic, and transcription factors in phenotypically and etiologically distinct forms of pediatric cataracts were evaluated. Methods: This cross-sectional study included 89 pediatric cataract subjects subtyped into 1) prenatal infectious (cytomegalovirus, rubella, and combined cytomegalovirus with rubella infection), 2) prenatal non-infectious, 3) posterior capsular anomalies, 4) postnatal, 5) traumatic, and 6) secondary, and compared to clear, non-cataractous material of eyes with the subluxated lenses. Expression of lens structure-related genes (Aqp-0, HspA4/Hsp70, CrygC), transcription factors (Tdrd7, FoxE3, Maf, Pitx 3) and profibrotic genes (Tgfβ, Bmp7, αSmA, vimentin) in surgically extracted cataract lens material were studied and correlated clinically. Results: In cataract material, the lens-related gene expression profiles were uniquely associated with phenotype/etiology of different cataracts. Postnatal cataracts showed a significantly altered FoxE3 expression. Low levels of Tdrd7 expression correlated with posterior subcapsular opacity, whereas CrygC correlated significantly with anterior capsular ruptures. The expression of Aqp0 and Maf was elevated in infectious cataracts, particularly in CMV infections, compared to other cataract subtypes. Tgfβ showed significantly low expression in various cataract subtypes, whereas vimentin had elevated gene expression in infectious and prenatal cataracts. Conclusion: A significant association between lens gene expression patterns in phenotypically and etiologically distinct subtypes of pediatric cataracts suggests regulatory mechanisms in cataractogenesis. The data reveal that cataract formation and presentation is a consequence of altered expression of a complex network of genes.

Electric field and Maxwell current density measurements made below thunderstorms at Pune (India) have been analyzed to study the charging processes occurring during dissipation stage of thunderstorms. These observations suggest that during the dissipation stage of thunderstorm different charging processes contribute to the cloud electrification depending on the type of thunderstorms. Our observations suggest that updraft may not be sufficient to activate charging mechanism inside cloud during the dissipation stage in small thunderstorms. However, in big thunderstorms, non-inductive charging mechanism may be active during the dissipation stage. The recovery curves of electric field and Maxwell current density measured during dissipation stage of inverted polarity thunderstorms suggests that inductive charging mechanism may also contribute to the thunderstorm electrification.

The association between aerosol and lightning has been investigated with long-term decadal data (2005–2014) for lightning, aerosol optical depth (AOD), relative humidity, and effective cloud droplet size. To understand the complex relationship between aerosol and lightning, two different regions with different climatic and weather conditions, a humid region R1 (22°–29° N, 89°–92° E) and an arid region R2 (23°–28° N, 70°–76° E) of northern India, were chosen for the study domain. The results show that lightning activity was observed to occur more over the humid region R1, i.e., 1141 days (1/3 of total days), than over the arid region R2, i.e., 740 days (1/5 of total days). Also, over the humid region R1, the highest lightning flash density was recorded as nearly 4.6 × 10–4 flashes/km2/day observed for 18 days (1.5%); on the contrary, over the arid region R2, the maximum lightning flash density was observed to be 2.5 × 10–4 flashes/km2/day and occurred for about 22 days (2.9%). The analysis shows that a nonlinear relationship exists between aerosol and lightning with a highly associated influence of relative humidity. A very significant positive and negative co-relation that varies with relative humidity has been observed between AOD and lightning for both humid and arid regions. This shows relative humidity is the key factor in determining the increase or decrease of lightning activity. This study also shows that the larger the cloud droplet size, the higher the relative humidity and vice versa. This study emphasizes that aerosol concentration in the atmosphere influences cloud microphysics by modulating the size of cloud droplets and thereby regulating the lightning frequency. The atmospheric humidity is the driving factor in deciding the positive or negative co-relationship between aerosol and lightning.

Present work addressed the variability of lightning flash count and persistence of Convective Available Potential energy (CAPE) during onset-withdrawal and active-break phases of Indian southwest monsoon (ISM) over central India region for the period 2014–2019. We have observed that higher lightning activity is during the prior to onset phase (June) period as well withdrawal phase (September–October) of Indian southwest monsoon season. During the break phase (mid-monsoon months, July and August), the monsoon trough shifts northwards; as a result, lightning activity does not cease totally and some lightning activity is still observed over study region. It is noticed that position of monsoon trough play an important role in the lightning activity and CAPE. The analysis clearly suggests high CAPE is a necessary condition for formation of thunderstorms during ISM period (June to September). From the station based CAPE data, it is seen that lightning activity is higher at a station Nagpur (close to the monsoon trough region) compared to a station Hyderabad (far away from monsoon trough). Further, the monsoon trough region remains conditionally unstable which generates lightning producing storms over the study region during monsoon season. Observations suggest that when monsoon trough is strong, entrainment of cold and dry air in the lower level from north of monsoon trough interact with warm and moist air from south of monsoon trough and can make the atmosphere conditionally unstable that helps in formation of thunderstorms over the study region during ISM.