Glaciers of the Tista basin represent an important water source for mountain communities and a large population downstream. The article presents observable changes in the Chhombo Chhu Watershed (CCW) glacier area of the Tista basin, the Sikkim Himalaya. The CCW contains 74 glaciers (> 0.02 km²) with a mean glacier size of 0.61 km². We determined changes in glaciers from the declassified Hexagon Keyhole-9 (KH-9) (1975), Landsat 5 Thematic Mapper (TM) (1989), Landsat 7 Enhanced Thematic Mapper Plus (ETM+) (2000), Landsat 5 TM (2010), and Sentinel-2A (2018) images. The total glacier area in 1975 was 62.6 ± 0.7 km²; and by 2018, the area had decreased to 44.8 ± 1.5 km², an area loss of 17.9 ± 1.7 km² (0.42 ± 0.04 km² a⁻¹). Clean glaciers exhibited more area loss of 11.8 ± 1.2 km² (0.27 ± 0.03 km² a⁻¹) than partially debris-covered and maximally debris-covered glaciers. The area loss is 5.0 ± 0.4 km² (0.12 ± 0.01 km² a⁻¹) for partially covered glaciers and 1.0 ± 0.1 km² (−0.02 ± 0.002 km² a⁻¹) for maximally covered glaciers. The glacier area loss in the CCW of the Sikkim Himalaya is 0.62 ± 0.5 km² a⁻¹ during 2000–2010, and it is 0.77 ± 0.6 km² a⁻¹ during 2010–2018. Field investigations of selected glaciers and climatic records also support the glacier recession in the CCW due to a significant increase in temperature (0.25 ^∘C a⁻¹) and more or less static precipitation since 1995. The dataset is now available from the Zenodo web portal: https://doi.org/10.5281/zenodo.4457183 (Chowdhury et al., 2021).

Since the first case of COVID-19 traced in India on 30th January, 2020, the total no. of confirmed cases is amplified. To assess the inter-state diversity in spreading potentiality of COVID-19, the exposure, readiness and resilience capability have been studied. On the basis of the extracted data, the outbreak scenario, growth rate, testing amenities have been analysed. The study reflects that there is an enormous disparity in growth rate and total COVID-19 cases. The major outbreak clusters associated with major cities of India. COVID-19 cases are very swiftly amplifying with exponential growth in every four to seven days in main affected states during first phase of lockdown. The result shows the vibrant disproportion in the aspects of, hospital bed ratio, coronavirus case-hospital bed ratio, provision of isolation and ventilators, test ratio, distribution of testing laboratories and accessibility of test centres all over India. The study indicates the sharp inequality in transmission potentiality and resilience capacity of different states. Every state and union territory are not well-prepared to contain the spreading of COVID-19. The strict protective measures and uniform resilience system must be implemented in every corner of India to battle against the menace of COVID-19.

The Sikkim Himalayan glaciers and glacial lakes are affected by climate change like other parts of the Himalayas. As a result of this climate variability in the Sikkim Himalaya, a detailed study of the Gurudongmar lake complex (GLC) evolution and outburst susceptibility assessment is required. Glacial lake volume estimation and lake outburst susceptibility assessment were carried out to reveal different characteristics for all four lakes (GL-1, GL-2, GL-3, and GL-4) from the lake complex. Each of these lakes has a moderate to very high potential to outburst. As the dam of GL-1 provides no retention capacity, there is a very high potential of a combined effect with the sudden failure of the moraine-dams of GL-2 or GL-3 located upstream. Temporal analysis of GLC using optical remote sensing data and in-field investigations revealed a rapidly increasing total lake area by ~74 ± 3%, with an expansion rate of +0.03 ± 0.002 km² a⁻¹ between 1962 and 2018 due to climate change and ongoing glacier retreat. The overall lake area expansion rates are dependent on climate-driven factors, and constantly increasing average air temperature is responsible for the enlargement of the lake areas. Simultaneously, changes in GLC expansion velocity are driven by changes in the total amount of precipitation. The deficit in precipitation probably triggered the initial higher rate from 1962 to 1988 during the winter and spring seasons. The post-1990s positive anomaly in precipitation might have reduced the rate of the glacial lake area expansion considerably.

Since the early 20^th century the Haora River, the lifeline of the Agartala city, Tripura, India, has been intensely used by the city dwellers for fulfilling their own needs. The dwellers, directly or indirectly are not only polluting the river water, but also altering the morphology and the dynamics of the river. The Haora River originated in Tripura, India but it has its confluence with the River Titas in Bangladesh. This river has a total length of about 61.2 km among which 52 km is flowing within Indian Territory. Within this 52 km length, three long stretches have been identified, where the course of the river as well as the flow has been changed due to anthropogenic activities. Starting from the International Boundary, individually those stretches cover 5.35 km, 4.74 km and 5.47 km of length respectively. For the detection of course change of the main Haora River 1932-2005 time period has been considered based on the availability of maps and images. Major activities, responsible for such changes are construction of distributaries (canal) for diverting flood water, dumping of huge brick waste of the brick fields along and within the river and dumping of market garbage along the bank. Excepting these three stretches, some other areas along the Haora River are also noticed where minor changes in river dynamics (formation of bars, course change, bank erosion, etc.) are initiated by construction of causeways, bridge piers and other anthropogenic activities.