The present study focuses on the neotectonics activity and related mass movement along the Eastern Ramganga River Basin (ERRB), Kumaun Himalaya, India. To understand the contemporaneous landform development, the quantitative analysis of drainage network is combined with field-based geomorphic attributes and recent seismicity data. The Ramganga River traverses across major thrusts, e.g., Main Central Thrust (MCT), Munsiari Thrust (MT) and Berinag Thrust (BT), and subsidiary faults, e.g., Namik Fault, Kaphli Fault, Hokara Fault, Kaphlikot-Ramari Fault and Ramganga Fault. Furthermore, the NNW–SSE trending faults (e.g., Naulara-Chilkiya Fault (NCF) and Nankana-Kapisar Fault (NKF) were also demarcated by means of characteristic geomorphic features in the upper catchment of the basin. The observed geomorphic elements such as uplifted fluvial terraces, several small to large waterfalls, fault facets, active and stabilized landslides, deflected and migrated streams, wide/straight river course converting into narrow passage, entrenched river channels, palaeo-channels and dissected hills etc. demonstrate symptomatic footprints of landscape evolution within the basin and also reveal that the thrusts/faults traversing through the ERRB are reasonably active. The field investigations are further verified by measuring various morphometric indices, results of which indicate elongated and asymmetric valleys, highly dissected drainage basin, high relief, sharp deflections in streams, slope breaks with remarkable values of stream length gradient index (SL) and steepness index (Ks). Further, we observed anomalous geomorphic expressions with possible surface deformation within thrust/fault zones as well as along anticlinal axis in the upper catchment which is characterized by higher slope, relief, accelerated erosion, incision, uplift and mass movements. Such features in the thrust/fault-fold belt of the region and recurrent seismicity appear responsible for triggering severe landslides under intense rainfall. The outsized disastrous landslides have resulted in destruction of human settlement, disconnecting road networks, damage of property and loss of lives particularly during the monsoon period. Therefore, we recommend that proper geological and geo-technical surveys are of utmost importance to identify susceptible sites all along the basin length.

This paper presents an insight on major ion chemistry and identification of solute sources in meltwater of Chaturangi glacier throughout the ablation period 2015 and 2016. The results indicate that meltwater is slightly acidic with Ca–HCO₃ and Mg–HCO₃ dominated hydrochemical facies. In meltwater, Ca²⁺ and HCO₃⁻ are the most dominant cation and anion, respectively. The Water Quality Index values show that the quality of meltwater is good for both the ablation seasons. An important factor governing the quality of water is the residence time for dissolving minerals from the rocks. Mineralogy of surrounding rocks and Gibbs plot suggest that the meltwater ionic concentration is mostly controlled by weathering of rocks with slight contribution from atmospheric aerosols. For meltwater, the average equivalent ratios of Na/Cl and K/Cl were calculated as 3.36 ± 1.29 and 2.29 ± 0.62 in 2015 and 1.39 ± 0.6 and 0.8 ± 0.2 in 2016, which are considerably higher than the marine aerosols (Na/Cl = 0.85 and K/Cl = 0.017), it also confirmed the less contribution of atmospheric input in meltwater. The petrographic analysis of surrounding rocks indicate positive relationship among the cations (Ca²⁺, Mg²⁺, Na⁺ and K⁺) and mineral abundance. Our observations suggest that the bedrock mineralogy and weathering reactions together with amount and composition of atmospheric inputs are the main sources of ions, dissolved in the glacier meltwater. It might be due to rate of chemical reaction which leads decomposition of rocks and leaching of minerals into the meltwater. Additionally, the geology of the area plays a significant as the influence of geology and climate on water quality is observed by the quantity and types of dissolved materials and amount of the sediment carried by the streams. The elevated proportion of Ca + Mg in total cations and high Ca + Mg/(Na + K ratios, 1.47 ± 0.14 in the year 2015 and 1.44 ± 0.28 in 2016 clearly reveal that the ionic composition is primarily controlled by carbonate weathering and partly by silicate weathering. Further, the low Na + K/TZ⁻ ratio (0.41 ± 0.02) and (0.22 ± 0.05) in 2015 and 2016, respectively also supports that carbonate weathering is main geochemical process controlling the hydrochemistry of meltwater. In addition, the ion denudation rate was calculated for both the years. The results show that the cation denudation rate of meltwater was 32.84 and 22.30 ton/km²/ablation during 2015 and 2016, respectively, whereas the anion denudation rate was found to be 205.43 in 2015 and 170.24 ton/km²/ablation in 2016.

Understanding the spatiotemporal monsoonal variability during the Holocene helps in understanding the rise and fall of many civilizations. In this study, a 2.65 m high palaeo lake sedimentary profile from the Kumaun Lesser Himalaya, Uttarakhand State, India was pollen analysed to reconstruct the variability in the monsoonal precipitation during the Middle Holocene. The study revealed that between ~7522 and 7216 cal yr BP, conifers dominated mixed broad-leaved forests occurred around the landscape of the study area, indicating a less cold and dry climate with decreased monsoon precipitation. Broad-leaved taxa during this phase show increased values considerably, indicating amelioration in climatic condition, which could be, in global perspective, broadly falling within the time-interval of the Holocene Climate Optimum (HCO; 7000–4000 BP). Between ~7216 and 6526 cal yr BP, dense conifers-dominated mixed broad-leaved forests transformed the conifers-dominated broad-leaved forests around the study area under a cold and drier climate with further reduction in monsoon precipitation. Subsequently, between ~6526 and 5987 cal yr BP, conifers-dominated broad-leaved forests continued to grow, but with lesser frequencies, around the study area under a comparatively less cold and dry climate with reduced monsoon precipitation. Finally, between ~5987 and 5817 cal yr BP, the frequencies of conifers-dominated broad-leaved forests further decreased around the landscape of the study area under a comparatively lesser cold and dry climate, probably indicating decreased monsoonal precipitation. Hence, the present study mainly showed the dominance of conifers forests around the study area between ~7522 and 7216 cal yr BP, ~7216 and 6526 cal yr BP, ~6526 and 5987 cal yr BP and between ~5987 and 5817 cal yr BP; however, broad-leaved forests also demonstrated increasing tendency between ~7522 and 7216 cal yr BP in the milieu of cold and dry climates. Moreover, the study also revealed that a lake was formed around 7522 cal yr BP along the Kulur River, a tributary of Saryu River around the study area and existed until 5817 cal yr BP.

The study evaluates the impacts of India’s COVID-19 lockdown and unlocking periods on the country’s ambient air quality. India experienced three strictly enforced lockdowns followed by unlocking periods where economic and social restrictions were gradually lifted. We have examined the in situ and satellite data of NO₂ emissions for several Indian cities to assess the impacts of the lockdowns in India. Additionally, we analyzed NO₂ data acquired from the Sentinel-5P TROPOMI sensor over a few districts of the Punjab state, as well as the National Capital Region. The comparisons between the in situ and satellite NO₂ emissions were performed for the years 2019, 2020 and up to July 2021. Further analysis was conducted on the satellite data to map the NO₂ emissions over India during March to July for the years of 2019, 2020 and 2021. Based on the in situ and satellite observations, we observed that the NO₂ emissions significantly decreased by 45–55% in the first wave and 30% in the second wave, especially over the Northern Indian cities during the lockdown periods. The improved air quality over India is indicative of reduced pollution in the atmosphere due to the lockdown process, which slowed down the industrial and commercial activities, including the migration of humans from one place to another. Overall, the present study contributes to the understanding of the trends of the ambient air quality over large geographical areas using the Sentinel-5P satellite data and provides valuable information for regulatory bodies to design a better decision support system to improve air quality.