BSIP study of Bakhira Lake sediments reconstructs 25,000 years of Indian Summer Monsoon history
On 10 September 2026, the Department of Science and Technology reported a Birbal Sahni Institute of Palaeosciences study that used magnetic minerals in Bakhira Lake sediments in Uttar Pradesh to track monsoon changes over 25,000 years.
Summary
Researchers of the Birbal Sahni Institute of Palaeosciences (BSIP), an autonomous institute of the Department of Science and Technology, measured magnetic minerals in sediments below Bakhira Lake in Sant Kabir Nagar, Uttar Pradesh, to reconstruct the Indian Summer Monsoon over about 25,000 years, from the Last Glacial Maximum to the present. The record identifies events such as the cold, dry Last Glacial Maximum with a weakened monsoon and the warmer, wetter Bølling–Allerød interval with stronger monsoon activity. Bakhira Lake is a perennial oxbow wetland in the Ghaghara–Rapti system formed by a cut-off of the Rapti River, one of Uttar Pradesh's largest wetlands, and was designated a Ramsar Site in 2022. The study, published in Palaeogeography, Palaeoclimatology, Palaeoecology, can improve monsoon models and water management in the Central Ganga Plain.
Key facts
- Study
- BSIP (DST) — environmental magnetism of lake sediments
- Site
- Bakhira Lake, Sant Kabir Nagar, Uttar Pradesh
- Span
- ~25,000 years, Last Glacial Maximum to present
- Lake type
- Oxbow wetland formed by cut-off of the Rapti River
- Ramsar
- Designated 2022
- Journal
- Palaeogeography, Palaeoclimatology, Palaeoecology
Practice MCQs 3 questions
Bakhira Lake, whose sediments were used in a BSIP monsoon study reported in September 2026, is located in which state?
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Correct answer: B — Uttar Pradesh
Bakhira Lake is in Sant Kabir Nagar district of Uttar Pradesh.
Bakhira Lake is an oxbow wetland formed by the cut-off of which river?
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Correct answer: A — Rapti
The lake lies in the Ghaghara–Rapti alluvial system and formed through the migration and cut-off of the Rapti River.
Consider the following about the Bakhira Lake study (2026): 1. Bakhira Lake was designated a Ramsar Site in 2022. 2. The record shows a strengthened Indian Summer Monsoon during the Last Glacial Maximum. Which of the above is/are correct?
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Correct answer: A — 1 only
Only statement 1 is correct. Bakhira became a Ramsar Site in 2022; the Last Glacial Maximum was cold and dry with a weakened monsoon.