As five-year old Ashwin runs full speed towards the Nullah Park’s tree house, his grandmother Priya settles below on the wooden park bench. She is soon joined by her daily group of walking buddies and the silver brigade is off for their evening walk. They pass two collegians who are discussing how best to go about their science project, while enjoying the waterfall view of the park is a couple who has taken respite from their daily grind of household responsibilities. Pune’s nullah parks are a unique concept that have transformed degraded sewage drains into planned eco-systems which support a variety of flora and fauna. Earlier these nullahs criss-crossing through the city were no more than dumping grounds full of piled construction debris and waste matter, often functioning as open air lavatories and sites for drunkards and hooligans. Polythene bags and refuse with pigs and buffaloes roaming were a common sight. Now with their conversion to nullah parks, they have become the lungs of the city while enhancing the beauty of the place where they have been created. Nullahs are storm water drains which have carved specific paths along the topography of the city. Over the years, these storm water drains became victims of neglect and encroachment. As storm water transverses, it provides a natural path for rain water to flow. Being waterways, during the monsoon the nullahs were in serious danger of flooding due to their clogged condition. Perhaps the very first nullah park in Pune was the Osho Teerth Park where one can stroll down the green pathways complete with small bridges over the streams and crystal clear waterfalls in a pleasing landscape with rocky outcrops. The park is where the city folk head to for some peace and solitude. But this very Zen like Japanese garden was once a 12 acre open air sewer. The place was more of a rubbish dump than a stream. The murky water running through here had been heavily polluted with garbage and sewage outflow. The stench from this eyesore was so disgusting that the people living around it finally decided to do something about it. In May 1990, Shunyo Foundation was initiated to develop this area in co-operation with the Pune Municipal Corporation and the Maharashtra State Government. Water management became the key to this ecological experiment. The main challenge was in making the 500 gallons of dirty water usable. Ingenious irrigation techniques were thought of to avoid the use of chemicals. Inspired landscape designing took place. Once the decision to turn the area around the nullah into a park was made, sustainable steps for its execution began. For purifying the water, the nullahs self sustaining system of cleansing themselves came in handy. Triple filtration of the water due to pebbles, stones and plants called the green bridge purified the water to about 70%. Along with a coconut choir mesh, the green bridge worked as filters which trapped suspended solids that were then degraded by bacteria and absorbed by the plants. A green bridge is a modification of the vertical eco-filtration system of nature and does not require electricity. The nullah water has good amounts of calcium and trees grow 7-10 times faster when watered with it making these parks a cost effective plantation in urban areas. After purifying the water, work on landscaping the garden was undertaken. Specific species of trees like bamboo were planted to prevent soil erosion, provide good ground cover and help set up an eco-system by attracting birds. Bamboo releases huge quantities of oxygen in the atmosphere and is easy to grow. Also its roots automatically act as a sieve to clean up the water. Grass covers in extensive quantities were essential for binding the soil together. While laying the grass beds, along with grass, shrubs were also planted. To counter the menace of mosquitoes, Gambusia which is a larvae eating fish was released into the nullah. The Osho Teerth Park was presented at the Rio Earth Summit, Brazil in 1992 as an indigenous development of a virtual garbage dump into a garden park. It was also presented at the California Environmental Health Association, USA and has been awarded citations by various organizations in India for its work done in eco sustainability. Taking a cue from it, other nullah parks have developed over the years. Today they are described as Shangri-La, a haven for those wanting a break from the city’s traffic and pollution. The water bodies and aquatic life here provides one with a sense of tranquility and calm. While regulars marvel at the beauty of the aesthetic environmental project, others find it hard to believe that these parks were once sewage spots with stinking mosquitoes. These parks, a much needed respite in today’s concrete jungle have become tourist spots with gurgling streamlets, grass lawns, walking tracks, variegated fare of ornamental plants and majestic trees.