Why in news?

The Sikkim government has informed the National Green Tribunal (NGT) that more than usual heavy rainfall — possibly a cloudburst — had preceded the glacial lake outburst flood (GLOF) event in the South Lhonak lake. The state government has based its conclusion on a report by the North East Space Application Centre (NESAC).

At least 40 people were killed 76 went missing in Sikkim in October 2023 after the South Lhonak Lake - a glacial lake situated in the state’s northwest at 17,000 ft - burst due to incessant rains.

What’s in today’s article?

• National Green Tribunal (NGT)
• Glacial Lake Outburst Flood (GLOF)
• North East Space Application Centre (NESAC)

National Green Tribunal (NGT)

• It was established in October 2010 under the National Green Tribunal Act 2010 for effective and expeditious disposal of cases relating to environmental protection and conservation of forests and other natural resources.
• It is a specialized body equipped with the necessary expertise to handle environmental disputes involving multi-disciplinary issues.
  • India became the third country in the world to set up a specialised environmental tribunal, only after Australia and New Zealand.

Structure & Members of NGT

• The Principal Bench of NGT has been established in New Delhi, with regional benches in
  • Pune (Western Zone Bench); Bhopal (Central Zone Bench); Chennai (Southern Bench) and Kolkata (Eastern Bench).
• The Chairperson of the NGT is a retired Judge of the Supreme Court.
  • Other Judicial members are retired Judges of High Courts. Each bench of the NGT will comprise of at least one Judicial Member and one Expert Member.
  • Expert members should have a professional qualification and a minimum of 15 years’ experience in the field of environment/forest conservation and related subjects.

Powers of NGT

• The Tribunal is not bounded by the procedure laid down under the Code of Civil Procedure, 1908. It is guided by principles of natural justice.
• The Tribunal is mandated to make and endeavour for disposal of applications or appeals within 6 months of filing of the same.
• NGT has the power to hear all civil cases relating to environmental issues and questions that are linked to the implementation of laws listed in Schedule I of the NGT Act.
  • It should be noted that the NGT has not been vested with powers to hear any matter relating to
    • the Wildlife (Protection) Act, 1972,
    • the Indian Forest Act, 1927 and
    • various laws enacted by States relating to forests, tree preservation etc.

Glacial Lake Outburst Floods (GLOFs)

• Glacial lakes
  • Glacial lakes are large bodies of water that sit in front of, on top of, or beneath a melting glacier.
  • Glacial lakes are formed when a glacier erodes and then melts, filling the depression created by the glacier.
    • They are typically found in high-altitude or polar regions.
    • The more the glacier recedes, the bigger and more dangerous the lake becomes.
  • Glacial lakes are generally divided into two main groups:
    • Ice-contact lakes: These lakes have glacier ice that terminates in the lake water.
    • Distal lakes: These lakes are distant from glaciers or ice sheets, but are still influenced by their presence.
• About GLOFs
• Glacial lakes are mostly dammed by unstable ice or sediment composed of loose rock and debris.
• In case the boundary around them breaks, huge amounts of water rush down the side of the mountains, which could cause flooding in the downstream areas — this is referred to as a GLOF event.
• Factors triggering GLOFs
  • GLOFs can be triggered by various reasons, including glacial calving, where sizable ice chunks detach from the glacier into the lake, inducing sudden water displacement.
  • Incidents such as avalanches or landslides can also impact the stability of the boundary around a glacial lake, leading to its failure, and the rapid discharge of water.

How did South Lhonak Lake Become Susceptible to GLOF?

• With the rising global temperatures, glaciers in Sikkim Himalayan have been melting rapidly, giving rise to many glacier lakes and expanding the already existing ones in the region.
• According to the Sikkim State Disaster Management Authority (SDMA), there are currently more than 300 glacial lakes in Sikkim Himalayan, and 10 (including South Lhonak Lake) have been identified as vulnerable to outburst floods.
• An earthquake of magnitude 4.9 in 1991 near the parent glacier feeding the South Lhonak Lake and the recent earthquake (6.9) in 2011 may have weakened the boundaries of the lake.
  • The recent incessant rains caused the lake to burst.

North East Space Application Centre (NESAC)

• NESAC is a regional space center in Umiam, Meghalaya that was established in 2000.
• It is a joint initiative between the Department of Space (DOS) and the North Eastern Council (NEC).
• It provides developmental support to the North Eastern Region (NER) using space science and technology.