Q. With reference to India, Didwana, Kuchaman, Sargol and Khatu are the names of (UPSC Prelims 2021)
Answer: saline lakes
Notes: The correct answer is [D] saline lakes. These locations are all found in the state of Rajasthan and represent significant inland drainage basins characterized by high salinity.

• Saline Lakes (Statement D – Correct): Didwana, Kuchaman, Sargol, and Khatu are salt-water lakes located in the Nagaur and Sikar districts of Rajasthan. These lakes are part of the Thar Desert’s endorheic (closed) basins where water evaporates, leaving behind concentrated salt deposits.
• Glaciers (Statement A – Incorrect): Glaciers in India are primarily restricted to the Himalayan ranges (e.g., Siachen, Gangotri). The arid climate of Rajasthan does not support glacial formations.
• Mangrove Areas (Statement B – Incorrect): Mangroves require coastal, brackish water environments. Major Indian mangrove sites include the Sundarbans (West Bengal), Bhitarkanika (Odisha), and Pichavaram (Tamil Nadu).
• Ramsar Sites (Statement C – Incorrect): While Rajasthan has Ramsar sites like Keoladeo National Park and Sambhar Lake, the specific lakes mentioned—Didwana, Kuchaman, Sargol, and Khatu—are not currently designated as Wetlands of International Importance under the Ramsar Convention.

These lakes are ecologically important and have historically been used for local salt production. Didwana, in particular, is known for the extraction of sodium sulfate rather than just edible salt (sodium chloride).