|Location||Southeast of Bengaluru city|
|Primary outflows||Varthur Lake|
|Catchment area||148 km²|
|Max. length||3.6 km|
|Max. width||1.4 km|
|Surface area||3.61 km²|
|Surface elevation||921 m|
Bellandur Lake (or Bellandur Kere, KN: ಬೆಳ್ಳಂದೂರು ಕೆರೆ/ಕೊಳ/ಹಳ್ಳ) is a lake which lies to the southeast of the city of Bangalore, and is the largest lake in the city. It is a part of Bellandur drainage system that drains the southern and the southeastern parts of the city. The lake is a receptor from three chains of lakes upstream, and has a catchment area of about 148 square kilometres (37,000 acres). Water from this lake flows further east to the Varthur Lake, from where it flows down the plateau and eventually into the Pinakani river basin. It is currently highly polluted with sewage. Since the lake is not developed tourism activities like boating, rowing are not available here.
Bellandur Lake is a major water body which is located in one of the three main valleys of Bangalore. It forms a part of Ponnaiyar River catchment, and water from Bellandur flows to Varthur Lake, ultimately joining the Pennar River. Currently, most of Bengaluru's treated and untreated sewage is let into this lake, severely polluting it, resulting in a depletion of wildlife in and around the lake.
Flora & Fauna
The lake was a prominent catchment area with a good green cover and was a watering hole for the region's numerous, indigenous wildlife. But 30 years of unplanned urbanization have taken a toll on the lake, now several species are gone from the area, including kingfishers, parrots, parakeets, wood pigeons, kites, king cobras, rat snakes, monitor lizards. As more and more large apartment complexes come up on the lakes shores, more such species will disappear.
Impact of Urbanisation
The conversion of watershed area of the lake to residential and commercial layouts has altered the hydrological regime while enhancing the silt movement – lowering water yield in the catchment, affecting the groundwater recharge. This has altered the integrity of the region, affecting all components of the lake catchment. A major portion of untreated city sewage (400+ million litres per day) is let into the lake, thus hampering the ecological balance of the system as the quantity of the pollutant entering the lake is beyond the neutralizing ability of the lake. This has led to the enrichment of nutrients, and has resulted in eutrophication within the lake.
The land around the lake is used as a dumping ground by builders and housing societies in the area. The combination of all these factors have led to a decline in the once robust eco-system of the lake which now resembles a stinking cesspool. Residents in neighboring areas complain of an odious stench that rises from the lake as a result of uninhibited sewage and chemical dumping from near by industrial units.
Time and again the Bangalore Government has attempted to take positive action to save the lake, but in the end, the maximum efforts come from citizens who plan plantation drives and cleanup programs around the lake. RTI activists like CH Ram have repeatedly brought the Lake's plight to the BBMP's attention, and have been promised affirmative action to save the lake. In 2010, the BBMP adopted a Lake Rejuvenation Program. Under this program, the lake got a new fencing all around its perimeter, a few saplings were planted and the lake was cleaned up. However, the sewage treatment plants and small industries that dispel their wastes into the lake, have still not been stopped and so the lake's main problems still continue.  
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