By Lucy Gibson
As one of the most popular landmarks in the city of Hyderabad, Hussain Sagar is the official “Heart of the World” having been named as such by the United Nations World Tourism Organisation for being the World’s Largest Heart-Shaped Mark.
Built by Hussain Shah Wali in 1562AD, Hussain Sagar Lake stands on the tributary of the River Musi and was constructed to meet the water and irrigation requirement of Hyderabad. Ever since, it has been of significance for connecting the twin cities of Hyderabad and Secunderabad. In its centre stands a statue of Buddha over 16 metres tall which was erected in 1992.
However, heavy anthropogenic pressures have changed the entire ecosystem.
The industrial expansion that began in the early 1970’s in the catchment area of the Hussain Sagar Lake and continuous encroachment in terms of both industrialisation and urbanisation has, in the past, polluted the Lake to levels way above international permissible limits. Additionally, its waters have become shallow due to siltation.
One cause of this siltation is that, during the Ganesh Chaturthi celebrations, Hussain Sagar usually witnesses thousands of idol immersions. As a part of this religious ritual, idols, along with flowers and other materials, are immersed into water bodies. In fact, according to the Greater Hyderabad Municipal Corporation (GHMC), over 80,000 Ganesh idols of various sizes were immersed in the Lake in 2019 which resulted in approximately 1500 tonnes of waste being collected from the Lake post festivities.
Studies indicate that such rituals reduce the depth of the water body. Over the last decade, the depth of Hussain Sagar has reduced from 60ft to 40ft, thus reducing the Lake’s capacity to hold water.
Besides adding silt, studies have also indicated that these immersions have increased the pollution levels of lakes. One 2009 studies shows that the chemical oxygen demand (COD) and biochemical oxygen demand (BOD) in the water body increased dramatically after the event. Some idols are made up of clay, plaster of paris, cloth, paper, wood, thermocol, jute, adhesive materials, and synthetic paints. Thermocol is non-biodegradable and some paints contain heavy metals such as chromium, lead, cadmium and mercury. When immersed, these chemicals dissolve slowly leading to significant alterations in water quality. The presence of heavy metals significantly increases in concentration after immersions. Such concentrations magnify at different trophic levels within food chains.
However, to say idol immersions are the main cause of this decline is unfair.
Equally significant, in terms of causation, are the sewage and pollutants being dumped into the lake from across the city. While originally constructed to meet the water requirements of the city, the Lake became the main sewage collection zone of the twin cities of Hyderabad and Secunderabad. According to the Andhra Pradesh Pollution Control Board data of 2012-13, every day 78 million litres of sewage and 15 million litres of industrial effluents flow into the lake. The two sewage treatment plants near the lake are insufficient to handle the wastewater load.
The resultant effect has been the loss of aquatic and terrestrial biodiversity of the Lake and its catchment area.
In light of this, in more recent years, an increased awareness of such problem has encouraged people to immerse more environmentally friendly idols that are smaller (so they dissolve faster) and are made of traditional clay and water soluble paints.
In fact, in 2020, there was little waste in the Lake as the Telangana Government banned Ganesh pandals, mass gathering, processions, and immersions due to the COVID-19 pandemic. As bad as the pandemic has been, environmentalists note that this will have a positive impact on the water and greenery around the Lake and Tank Bund as well. In fact, recent monitoring by the Telangana Pollution Control Board has shown that there is an increase of dissolved oxygen levels and biological oxygen demand levels have decreased.
In addition, on the 11 September 2020, it was announced that Hyderabad Metropolitan Water Supply and Sewerage Board will construct 17 new Sewage Treatment Plants in the catchment area of Hussain Sagar Lake. This plan, in increasing the sewage treatment capacity in the city will reduce an additional source of water pollution and contamination.
While COVID-19 has brought serious consequences for so many around the world, it has also shown us that, if allowed, our environments can recover.
We must allow them to continue to do so.
Lakes of India 