The ecologically subsidised city
Context:
- Kolkata’s wetland conservation and ecological importance
Rural ecological reference:
- A renowned environmentalist discovered that kolkatas waste water is detained in shallow water bodies which serve as oxidation ponds because of the presence of algae.
Under the open tropical sun
- Ghosh discovered that water undergoes change, getting comprehensively treated and cleaned as the bacteria disintegrate and the algae proliferate, serving as food for fish.
- The treated water is used by villagers in the area to grow vegetables and paddy.
Significance of discovery:
- It is considered a remarkable ecological wisdom on the part of largely illiterate villagers, based on knowledge of local conditions and wetland hydrology.
Ramsar site:
- The 125 sq km area of the wetlands were recognised internationally in 2002 as a ‘Ramsar site due to the efforts of Ghosh.
World’s largest organic sewage treatment plant:
- Kolkata is fortunate to be home to the world’s largest organic ‘sewage treatment plant’, the wetlands.
- Unobserved by the rest of the world, sun-fed algae and the bacteria in the sewage perform this wondrous function.
- The capacity to treat 750 million litres of wastewater per day. In monetary terms it would be over $25 billion (Rs. 162,500 crore) annually.
- These wetlands are also home to a wide variety of aquatic life, vegetation, and hundreds of species of birds
UN Millennium Ecosystem Assessment
- In 2005, the UN Millennium Ecosystem Assessment found ecological degradation to be more prominent within wetlands than any other ecosystem on Earth.
