Covered on one side by the Otteri Nulla, the concrete walls of a polytechnic institute on the other, and a cemetery on the third lies Chennai corporation’s best-kept secret, the Otteri Eco Park or the Tropical Dry Evergreen Forests of Otteri (formerly known as the garbage dumping yard of the city).

For decades, this patch of land was filled with waste from posh hotels and hospitals and construction debris and other forms of toxic waste. “So much of waste had been dumped that it became a mound measuring about 30 foot,” says site manager Arul, who has been associated with the project from 2005 when the then corporation commissioner started it.

Biologists who worked on the project adopted the bio-remedation process (the process of decontaminating the soil using natural plants and microbes) to transform the dumping ground into a forest. “We put a layer of soil over the garbage dump and started planting trees, shrubs and grass by carefully choosing the natural species of the region. The roots of these plants will absorb the toxic waste, break down its complexity, and, over a period of time, free the soil from all toxicants,” says botanist, Dr Ilangovan, who worked on the project.

Barring a few dry patches, the process seems to have worked its magic. The dumping yard is gradually turning into a little haven for avian and reptile residents. “But, it is just beginning to take shape and needs assistance for a few more years until the root systems reach the groundwater table. After that, the vegetation does not need our support,” says botanist, Dr Karthigeyan of the Pitchandikulam Forest Consultants that is currently maintaining the eco-park.

The park contains 15,000 plants of 105 indigenous species including vennandai, irumbuli, pungan and vembu besides several shrub and grass varieties.