Explore the vast range of titles available.

The rise in urban air temperature has forced the researchers to look for nature-based solutions to resolve the problem sustainably. Urban waterbody plays a multidimensional role in the well-being of the city by catering to its economical, ecological, and socio-cultural needs. It can offer a potential solution for urban heat attenuation, but its effect on outdoor thermal comfort is contentious in humid subtropical climate. This study investigates the thermal impact of waterbody on its surroundings in humid subtropical climate by adopting a human centric approach. Waterbody impact on ambient air temperature, PET, and UTCI are evaluated and compared for a better understanding of its thermal impact on nearby surroundings. This study employs a CFD-based simulation model Envi-met for microclimate analysis. The results show that a dynamic waterbody lowers the ambient air temperature during daytime in summer of its nearby surroundings in humid subtropical climate. Maximum cooling is observed in open mid-rise LCZ where the cooling impact range is 140 m with the amplitude of 2.59 °C and compact low-rise LCZ exhibits minimum cooling of the identified LCZs with the cooling impact ending 24 m from waterbody edge with amplitude being 0.131 °C in the study area. Air temperature, UTCI, and PET do reflect the same trend when moving away from the waterbody in large low-rise LCZ, but it decreases drastically in open mid-rise LCZ and is non-existent in compact low-rise. This result provides an insight on the impact of waterbody on thermal comfort in its surroundings in humid subtropical climate, thus assisting urban planners and designers in making context-specific holistic decision.

As in many other parts of the world, the urban areas of the South Asian region are increasingly expanding. While cities today are the heart of commercial, technological and social development, they are also vulnerable to a variety of natural and anthropogenic threats. The complex urban infrastructure, and the ever-expanding population in cities, exacerbate the impacts of climate change and increase the risk of natural hazards. Throughout history, various hydrological disasters including floods, tidal surges, and droughts, and non-hydrological disasters such as earthquakes, landslides, and storms have led to catastrophic social, economic and environmental impacts in numerous South Asian cities. Disaster risk reduction is therefore central to ensure sustainability in urban areas. Although Nature-based Solutions (NbS) are identified as a promising strategy to reduce risk and increase resilience, there appears to be a lack of evidence-based approaches. NbS are measures that can be practiced to obtain benefits of nature for the environmental and community development through conserving, managing, and restoring ecosystems. Against this backdrop, the South Asian cities provide opportunities to evaluate capacities for achieving Nature-based Resilience (NbR) through NbS. This study documents insights from five cities of five different countries of the South Asian region which are subjected to a wide array of disasters: Barishal (Bangladesh), Phuentsholing (Bhutan), Gurugram (India), Kathmandu (Nepal), and Colombo (Sri Lanka). The primary objective of this study is to provide evidence on how NbS are being practiced. Thus, some success stories in cities under consideration are highlighted: restoration of natural canals through integrated development plans and community participation (Barishal), concepts of Gross National Happiness (GNH) and minimal nature interventions (Phuentsholing), “Greening cities’’ including eco-corridors, vegetation belts, biodiversity parks (Gurugram), proper land use planning aims at different disasters (Kathmandu), and wetland restoration and management with multiple benefits (Colombo). These cases could therefore, act as a “proxy” for learning from each other to prepare for and recover from future disasters while building NbR.

Air temperature in urban street canyons is increased due to the morphed urban geometry, increased surface area, decreased long wave radiation and evapo-transpiration, different thermo-physical properties of surface materials and anthropogenic heat which results in thermal discomfort. Outdoor thermal stress can be mitigated substantially by properly orienting the canyons. It is crucial for the urban planners and designers to orient street canyons optimally considering variable local climatic context. It is important especially for cities in warm humid climatic context as these cities receive higher insolation with higher relative humidity and low level macro wind flow. This paper examines influence of canyon orientation on outdoor thermal comfort and proposes the optimum canyon orientation for the Rajarhat Newtown, Kolkata – a city in warm humid climate zone. Different scenarios are generated with different orientations. Change in air temperature, wind speed, Mean Radiant Temperature (MRT) and Physiological Equivalent Temperature (PET) of different scenarios are compared to find out the optimum orientation by parametric simulation in . Analysing the simulation results it is observed that orientation angle between 30°–60° to north performs the best for the study area of the Rajarhat Newtown. The findings of this research will be helpful for the planners to orient the street canyons optimally for future development and extension of the Rajarhat Newtown, Kolkata.

Water historically facilitated cities to survive, sustain, celebrate and create distinguished identities. This can offer livelihood, wisdom, culture, entertainment, sensibility, and most importantly nature connect, be it river, lake, pond, stream or fountain. Diminishing qualitative and quantitative presence of water bring rising crisis and risks to cities in the recent period. This paper explores whether, in addition to multiple eco system services (ESS), urban water can provide urban risk mitigation while celebrating nature connect and natural ecological processes. Green Infrastructure (GI) offers ESS as complementary service to engineering Infrastructure. Its potential as an urban risk mitigation tool is attracting urban authorities to use it as a resiliency tool. The Green Resilient Infrastructure (GRI) can help towards social, economic and environmental sustainability with the additional advantage of mitigation. Urban water management through GRI can resolve problemslike flooding, water scarcity and other associated problems like urban heat island (UHI), pollution, etc. India’s urban growth rate is unprecedented now and cannot offer quality living standards; there is an opportunity to make substantial improvement to this deteriorating urban climate using GRIs. The paper reviews the issue further into policy and refers to two Asian initiatives. In Kyoto City, successive landscape policy formulation and implementation has helped the city to preserve water as an essential urban element, and to mark celebrations with its pristine rivers. The city is now equated with most sought-after urban living quarternestled within nature; and visibility of urban waters add beauty and safety both. China’s sponge city mission is another case where struggling cities are relying on water-based GIs to convert them into GRIs to survive and celebrate urban lives. Both these cases are learning lesson for emerging countries like India and every city has a future with water to celebrate and manage risks.

South Asian countries face a disproportionate impact from disasters due to their unique topography, poverty, low literacy rates, and socio-economic status. Human activities, such as unplanned urbanization and poorly designed rural road networks, have further contributed to disasters in the region. The article explores the potential of nature-based solutions (NbS) as a means of addressing these challenges through the integration of green, blue, and grey infrastructure. The analysis evaluates the significance of NbS and examines policies and regional cooperation in Bangladesh, Bhutan, India, Nepal, and Sri Lanka, highlighting the importance of incorporating NbS into national policies and promoting collaboration among these countries. The study identifies the current low implementation of NbS in South Asia, with limited research in this area. While there are existing policy tools related to coastal zone management, water, forest, and urban development, policies related to NbS should be coherent, connected, and integrated with natural resources, climate change, disaster risk reduction, and socio-economic growth to achieve sustainable development in the region. Overall, the article emphasizes the need for effective policy implementation and research to enhance resilience to climate change and promote sustainable development in South Asia.

In Indian cities where streets are the only affordable outdoor public space, pedestrians are always exposed to extreme heat related health risk. However, it’s a challenge to reduce heat stress in existing streets characterized by asymmetrical urban configuration. Integrating vegetation without reconstituting the original orientation and geometry is one of the feasible ways to alleviate stress. Therefore, current study focuses to analyse the heat stress reduction potential of urban greenery strategy in asymmetrical urban configuration from spatiotemporal perspective. It initiates with the selection of commercial streets in extreme hot climate with an on-site measurement of its climatic and morphological attributes. Furthermore, it leads to the classification and prioritizing of street's sections linked to hot-spots determined by varied sky view factor and asymmetrical aspect ratio. Finally, an Envi-Met model with iterated scenarios at the building and street levels is developed, incorporating three strategies (trees, grass, green-walls). The impact of heat related health risk is quantified using a thermal index Universal Thermal Climate Index along with air temperature and mean radiant temperature. The results suggested that due to asymmetricity a fixed strategy would not be applicable across the street. The highest reduction was observed by trees in asymmetrical sections while lowest was recorded by green-wall. However, it would be worthwhile to adopt green-wall along with dense tree’s (leaf area density, 0.3) in order to reduce the heat stress in deeper sections. The evidence-based integration of Urban greenery can assist planners and designers in mitigating extreme heat stress in similar complex urban environment.

In Indian cities, where streets are the only affordable public space, thermal-climatic conditions have a significant impact on pedestrian activity and comfort. However, narratives are insufficient on pedestrian risk assessment in asymmetrical urban settings. Therefore, current study investigates the potential of thermal stress mitigation in the context of human biometeorological assessment in asymmetrical urban settings of Bhopal city. It initiates with the selection of a commercial street in tropical climate of Bhopal (Koppen climatic classification, Aw) with the measurement of its metrological and morphological attributes. Furthermore, it leads to an assessment of thermal stress utilizing physical survey and Envi-met simulations including the identification of critical spots. Finally, development of iterated scenario considering one major and local street with five varied street sections in symmetrical/asymmetrical condition for the EW, NWSE and NS orientation. The efficiency of mitigation measures in cooling the outdoor stress area was analysed by using Universal Thermal Climate Index (UTCI) along with mean radiant temperature (MRT) from a spatiotemporal perspective. The highest stress reduction was observed in higher asymmetrical section while lowest was recorded by lower symmetrical section. However, it is recommended to integrate high asymmetrical sections in complex urban area which can provide a better reduction (average UTCI by 3 °C, average MRT by 7 °C) to outdoor stress due to their ability of regulating efficient wind flow and shielding radiation. The evidence-based selection of street orientation and openness can adopt to optimize the urban configuration in similar climates to improve streetscape and activities from an environmental quality perspective.

The Indian Himalayan region (IHR) is prone to multiple hazards and suffers great loss of life and damage to infrastructure and property every year. Poor engineering construction, unplanned and unregulated development, and relatively low awareness and capacity in communities for supporting disaster risk mitigation are directly and indirectly contributing to the risk and severity of disasters. A comprehensive review of various existing survey forms for risk assessment has found that the survey questionnaires themselves have not been designed or optimised, specifically, for hill communities. Hill communities are distinctly different from low-land communities, with distinct characteristics and susceptibility to specific hazard and risk scenarios. Previous studies have, on the whole, underrepresented the specific characteristics of hill communities, and the increasing threat of natural disasters in the IHR creates an imperative to design hill-specific questionnaires for multi-hazard risk assessment. The main objective of this study is to design and apply a hill-specific risk assessment survey form that contains more accurate information for hill communities and hill-based infrastructure and allows for the surveys to be completed efficiently and in less time. The proposed survey form is described herein and is validated through a pilot survey at several locations in the hills of Uttarakhand, India. The survey form covers data related to vulnerability to earthquake (rapid visual screening), flood, high wind, landslide, industrial, non-structural falling hazards and fire hazards in the building, and climate change. SWOT (strengths, weaknesses, opportunities and threats) analysis of this study states that the proposed form has the advantages of being self-explanatory and pictorial, includes easy terminology, and is divided into various sections for better understanding by surveyors. This survey form has the weakness of being limited to specific hazards. There are opportunities for the form to be applied to other Himalayan countries like Bhutan, Nepal and Pakistan. When it is applied internationally, the options available in the questions may differ. The application process confirmed that the survey questionnaire performed well and met expectations in its application. The form is readily transferrable to other locations in the IHR and could be internationalised and used throughout the Himalayas.

Urban flooding is one of the major issues in Dehradun city. Lack of preparedness and lack of flood hazard zonation at city level resulted in increasing number of life losses every year. This research aims to evaluate urban flood hazard index (UFHI) and generate flood hazard zonation map, which can be used for prioritizing flood mitigation strategies and efficient allocation of resources in Dehradun city. UFHI is evaluated by linear combination of weighted overlay analysis of indicators using multiple criteria decision analysis. Here Satty’s AHP matrix is used for determining the weightage of each indicator. These indicators are integrated in geographic information systems as layers, resulting in a composite index map. Remote sensing data from Landsat 8 OLI, 2015; DEM 2013 of CARTOSAT-I data, and Survey of India toposheets, are used for creating base layer of the city. Six indicators which include, elevation, slope, drainage density, land use/land cover (LULC) runoff, flood water depth, and distance from river stream, are used for evaluation. As a result of analysis, urban flood hazard zones are identified and classified into—very high risk with 10 wards (16.67%), high risk with 20 wards (30.33%), medium risk with 22 wards (36.67%) and low risk with 8 wards (13.33%); out of the total 60 wards (smallest administrative unit) in city. The study indicates that two parameters namely LULC runoff and proximity to river stream have a direct co-relation to high flood hazard zones in Dehradun city. As a further scope of research, a greater number of indicators and micro-level studies can be taken up for more accurate results.

Urban Heat Islands (UHIs) pose a significant challenge to densely populated cities of India, intensifying heat stress and impacting public health, energy consumption, and urban sustainability. This study aims to identify Urban Heat Stress Risk in Mumbai (India) through the heat stress event of April-May 2024 using satellite data and by assessing thermal stress risk through a systematic approach combining urban weather modelling and in-situ observations along with vulnerability and exposure of the residents. Satellite-derived surface temperature data is analyzed to detect spatial patterns of UHI hotspots across the region. To deepen the understanding of thermal dynamics, the Weather Research and Forecasting Model with Urban Canopy Model (WRF-UCM) is employed, utilizing Local Climate Zone (LCZ) global data to simulate the Universal Thermal Climate Index (UTCI). A nested domain structure with spatial resolutions of 3*3 km, 1*1 km and 333*333 m are used to capture regional and localized variations of urban weather parameters. Validation of the WRF-UCM simulated meteorological variables is carried out using data from 36 Automatic Weather Stations across Mumbai (India). A correlation analysis between satellite-derived UHI hotspots and validated model results provides comprehensive insights into heat stress distribution. The findings highlight critical zones experiencing increased heat stress. The vulnerability and exposure index formulated through the Principal Component Analysis tool helped as additional overlaid layers to assess the risk over the study area, serving as an additional tool for urban planning interventions and policy recommendations related to heat stress risk.