The mangrove ecosystem of Sundarbans region plays a significant ecological and socio-economic role in both India and Bangladesh. An increase in coastal human settlements makes the area more vulnerable to natural disasters such as tsunamis and cyclones. Mangroves, as an exclusive group of plants, provide many ecological services such as reducing the impacts of cyclonic storms and gales and minimizing the sea level rise due to global warming. Sundarbans were facing immense destruction due to super cyclones during the past years. The present study investigated the ecological disturbance caused by the cyclone Amphan in Indian Sundarbans using remote sensing multispectral imagery. The pre and post-cyclonic Landsat data were analyzed to quantify the damaged area in Sundarbans due to the effect of the cyclone, Amphan. Normalized Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) were used to estimate the vegetative changes or losses that occurred due to the cyclone. Normalized Difference Water Index (NDWI), Normalized Difference Bareness Index (NDBaI) and Normalized Difference Salinity Index (NDSI)) were the other indices used to study the effects of cyclone. The study found that from pre to post-cyclonic period, mangroves reduced from 1,851.88 km 2 to 1,643.74 km 2 and about 50.18 km 2 of vegetation becomes sparse. High salinity values were observed during the postcyclonic period which indicated that the super cyclone resulted in saltwater intrusion. From pre to post cyclone, NDBaI results showed an increase in barren land from 908.13 km 2 to 1,365.57 km 2 .

On the windward side of Western Ghats, the frequency of landslides has significantly increased in recent years. Kerala had catastrophic landslides and floods in 2018, 2019, 2020, and 2021, resulting in loss of lives and property. On October 2021, a cloudburst occurred in middle Kerala, causing multiple devastating landslides in districts of Kottayam and Idukki. The study focused on how the topographic, physical, geological, and anthropogenic factors in the windward slope of the Western Ghats influence the occurrence of landslides. The landslide susceptibility was analyzed using the frequency ratio method on the basis of recently occurred landslide locations in the Manimala river basin, with special reference to Kootikal. The impact of each factor was analyzed against the GPS coordinates of landslide locations to estimate the frequency ratio value. The findings revealed that the torrential rainfall experienced in Kerala and the anthropogenic activities, especially the watershed management work performed in the area, significantly increased landslide susceptibility of the basin. About 5% of Manimala river basin is highly susceptible to landslides, and this area comes under the Kootikal sub-basin. The study recommends a rigorous geophysical assessment on the influence of watershed management operations on a landslide and an EIA of roads in the Kootickal region.