HIGHLIGHTS. Sub-watershed prioritisation using GIS and RS approaches is essential for better watershed management.Novel methods like PCA and LULC were introduce

Uncontrolled growth in population is the cause of the unplanned, rapid, and unsustainable expansion of urban areas. This has led to a deterioration of environmental conditions for both global and local ecosystems. This research investigates the Urban Heat Island (UHI) phenomenon in Bengaluru and Hyderabad, India, including its spatial and temporal distribution and relation to air pollution. The investigation was conducted in both study locations during the summer and winter seasons, with data spanning from 2001 to 2021. The findings reveal that the maximum UHI intensity in both cities varies seasonally, with the highest values observed during the summer and the lowest during the winter. Annual maximum UHI intensities range from 4.65 °C to 6.69 °C in Bengaluru and from 5.74 °C to 6.82 °C in Hyderabad. The average UHI intensity also exhibits seasonal and annual variations, with the UHI effect being particularly pronounced in Bengaluru. In addition, the study provides the Urban Thermal Field Variance Index (UTFVI), which reveals that both cities consistently face intense UHI impacts throughout the year, greatly affecting the quality of life. Additionally, hotspot analysis reveals an increasing trend in UHI-affected areas over the years in both cities. The study also highlights air pollution concentrations and shows relationships between land surface temperature (LST) and air pollutants, emphasizing the need to alleviate urban heat, enhance air quality, and promote sustainability. This underscores the importance of UHI dynamics in urban environmental management and public health. This study enhances comprehension of UHI dynamics in swiftly urbanizing areas, providing a novel viewpoint on the complex interconnection between urbanization, climate, and air quality. These insights help develop sustainable urban strategies, reducing the negative effects of uncontrolled urbanization and benefiting local communities and the global ecosystem.

Sub-watershed prioritization using morphometric analysis and multi-criteria decision-making (MCDM) techniques is a systematic approach to identifying and ranking sub-watersheds based on their susceptibility to soil erosion. This helps in implementing targeted soil conservation measures. In this study, sub-watersheds in the Narangi basin are prioritized by employing morphometric analysis integrated with advanced MCDM techniques, including additive ratio assessment (ARAS), complicated proportional assessment (COPRAS), multi-objective optimization by ratio analysis (MOORA), and the technique for order preference by similarity to ideal solution (TOPSIS). Weights for various MCDM methods are determined using the criteria importance through an inter-criteria correlation approach (CRITIC: criteria importance through inter-criteria correlation method), while geospatial techniques ensure precise spatial analysis. The results provide a unified ranking of sub-watersheds, revealing that sub-watershed 3 (SW3) and SW9 are in the high-priority soil erosion category; SW1, SW2, SW5, and SW8 are medium-priority; and SW4, SW6, SW7, and SW10 are low-priority. This comprehensive and sustainability-oriented approach equips decision-makers with robust tools to identify and manage sub-watersheds at risk of soil erosion, ensuring the long-term sustainability of land and water resources. This study aligns with sustainable development goal 15 (life on land) and promotes sustainable land use practices to combat soil degradation.

Soil erosion is a major global environmental problem, reducing soil fertility, crop yields, and causing economic losses. To tackle this effectively, it is essential to prioritize sub-watersheds using advanced techniques that support better planning and sustainable management. In this study, the delineation of the seven sub-watersheds (SWs) was carried out using a minimum third-order stream as the threshold. This study employs an integrated approach combining morphometric analysis, multiple criteria decision-making (MCDM) including additive ratio assessment (ARAS), technique for order of preference by similarity to ideal solution (TOPSIS), multi-objective optimization by ratio analysis (MOORA), simple additive weighting (SAW), and principal component analysis (PCA) to prioritize sub-watersheds in the Potteruvagu basin. The MCDM method used weights derived from the criteria importance through intercriteria correlation (CRITIC) method. The novelty of this study lies in its innovative application of MCDM techniques, synergistically combined with morphometric analysis and PCA for soil erosion priority. These novel methodologies enable precise and accurate analyses, facilitating the creation of a unified ranking system for each sub-watershed. The results classify SW5 and SW6 as high-priority soil erosion sub-watersheds, SW1 is a medium-priority soil erosion sub-watershed, and SW2, SW3, SW4, and SW7 are ranked low-priority soil erosion sub-watersheds. The results enable targeted soil erosion management, which directly helps with sustainable development goals (SDGs) such as SDG 6 (clean water and sanitation) and SDG 15 (life on land). This new framework makes it easier to make decisions based on facts for long-term planning and protection of watersheds.

Prioritisation of sub-watersheds (SWs) is becoming increasingly important in the conservation of natural resources, particularly in watershed planning. In this study, sub-watershed for the Neyyar basin was prioritised using three methods: morphometric analysis, principal component analysis (PCA) and hypsometric analysis. Morphometric analysis and hypsometric analysis were carried out using remote sensing (RS) and geographic information system (GIS) techniques, while PCA was performed for dimensionality reduction of morphometric parameters. The watershed was divided into 11 sub-watersheds (SW1–SW11), and each sub-watershed was given priority. To rank and prioritise SWs, 15 morphometric parameters were selected from the quantitative measures of morphometric analysis, including linear, relief, and areal. PCA was used to rank and prioritise SWs based on three highly correlated morphometric parameters. The hypsometric integral (HI) values were determined using the elevation relief ratio approach, and HI values were utilised to prioritise SWs. For both methods, such as morphometric analysis and PCA, a higher priority has been given to SW1. Using hypsometric analysis, higher priorities have been assigned to SW1, SW7, SW8, SW9, SW10 and SW11. The most common SWs that belong to the same priority of SWs and have a high correlation between them among the three methods are SW1, SW2, and SW5.The results of this analysis indicate that SW1 is a common high priority area with a significant risk of soil erosion, runoff and peak discharge. Therefore, decision-makers may utilise the high-priority sub-watershed to guide planning and development, measure conservation efforts and manage the land to prevent.

Air pollution is one of the grave concerns of the modern era, claiming millions of lives and adversely impacting the economy. Aerosols have been observed to play a significant role in negatively influencing climatological variables and human health in given areas. The current study aimed to study the trend of aerosols and particulates on daily, monthly, seasonal, and annual levels using a 20-year (2002–2021) daily mean aerosol optical depth (AOD) product released by moderate resolution imaging spectrometer (MODIS) sensors for the Hyderabad district in India. The results of the daily mean analysis revealed a rising trend in the number of days with severe AOD (>1), whereas examinations of the seasonal and monthly mean data from 2017 through 2022 showed that peak AOD values alternated between the summer, autumn, and winter seasons over the years. Trend analysis using Mann–Kendall, modified Mann–Kendall, and innovative trend analysis (ITA) tests revealed that AOD increased significantly from 2002 through 2021 (p < 0.05; Z > 0). Furthermore, correlation analysis was performed to check for correlations between AOD levels and certain meteorological factors for the Charminar and Secunderabad regions; it was noticed that temperature had a weak positive correlation with AOD (p < 0.05; r = 0.283 [Secunderabad] – p < 0.05; r = 0.301 [Charminar]), whereas relative humidity developed a very weak negative correlation with AOD (p < 0.05; r = −0.079 [Secunderabad] – p < 0.05; r = −0.109 [Charminar]).