Articles by Sanjana Alex

One of the characteristic features of a lake is its colour.  You may have noticed that the water in many lakes in Bengaluru is green, and not blue, as you might have imagined it to be. This is due to the presence of algae. Algae are microscopic plants that contain chlorophyll which is the pigment that gives it a green colour. While some amount of algae is healthy for the lake ecosystem, excess algae can be harmful and is an indicator of a polluted and nutrient-rich lake. Lakes rich in nutrients such as nitrogen and phosphorus are called eutrophic lakes,…

Due to rapid urbanisation and unplanned development, Bengaluru’s groundwater is getting increasingly contaminated. This issue requires urgent attention as approximately 40% of the city's population depend on groundwater (borewells, open wells and tankers) for their daily water needs such as drinking, cooking and bathing.  Contaminated groundwater could lead to health issues if it is directly consumed. If used for agricultural purposes, it could even enter the food chain.  Residents across the city have reported that borewells discharge coloured or smelly water. This indicates percolation of sewage and chemicals into the water table. Discolouration, cloudiness and bad odour are some of…

Traditionally, Bengaluru’s lakes stay dry for a couple of months, and fill up during the monsoons. This made it easier for potters, brick makers and farmers to collect silt from lakes. But due to climate change, rapid urbanisation and unplanned development, more lakes have been drying up for longer periods of time. An article by Times of India states that “According to BBMP, about 50% of the lakes have water less than half of their holding capacity. Some of them have gone dry and in others, the water level is fast depleting”. Sowl Kere, Kannamangala lake, Arakere, Sarakki, and Yelahanka…

Many lakes in Bengaluru, such as Kaikondrahalli, Kasavanahalli and Kalkere lakes, have foamed before. But the quantity of foam in Varthur and Bellandur lakes are alarmingly high.  In our previous article, we saw that fire occurs in Bellandur and Varthur lakes mainly because about 40% of the city's sewage is discharged into the catchment areas of these lakes. Apart from sewage, industrial effluents and solid waste are also dumped into these lakes. In some circumstances, this can cause the formation of foam. Foam in both Bellandur and Varthur lakes usually form during the pre-monsoon and monsoon season, when there are heavy…

Bengaluru, once known as the 'City of Lakes', has made national and international headlines as the 'City of Burning Lakes'. Lakes in Bengaluru have caught fire several times - mostly at Bellandur lake, but also in other parts of the city. The fire burns for hours, polluting the air with smoke and creating a public health hazard. Bellandur Lake, the city’s largest lake, has burst into flames many times in the recent past. The first instance was in May 2015, and then again in August 2016, February 2017, and January 2018. The 2018 fire lasted 30 hours, with smoke engulfing…

Bengaluru’s lakes have been in the news for pollution, froth, fish kill and even fire. Despite the government investing crores of rupees into reviving these lakes, and widespread citizen engagement, not much has changed. While the main reason is the lack of coordination between government departments, the absolute lack of science-based solutions is also a major gap. In this context, Ashoka Trust for Research in Ecology and the Environment (ATREE) and Biome Environmental Trust (BIOME) have developed the ‘Bangalore Citizen Science Lakes Dashboard’ to share knowledge and best practices for better management of lakes. We created a series of system…