In the context of Sikkim's hydrological network, which geological feature acts as the primary snow and ice reservoir feeding perennial streams like the Teesta and Lachen rivers?

💡 Solution & Explanation

The high-altitude glaciers situated along the Greater Himalayan range in northern Sikkim, such as the Zemu Glacier, act as perennial ice and snow reservoirs feeding rivers like the Teesta and Lachen throughout the year. Subterranean limestone aquifers and seasonal snowfields on lower hills do not sustain large perennial flows because lower hills lack permanent snow cover. Glacial meltwater combined with summer monsoon rainfall sustains the high discharge volumes utilized for hydroelectric power generation in Sikkim.