As part of a series on young environmentalists in the BBC's Generation Next season, Soutik Biswas reports from Bihar on youngsters creating an oasis in the heart of one of India's most polluted and lawless cities.
In busy and chaotic Patna, capital of Bihar, one of India's most backward and poorest states, a 10-acre farm has been converted into the city's only bio-reserve, by children. They belong to Taru Mitra (Friends of Trees), a group of youngsters committed to preserving the environment.
The children have planted over 30 street side gardens Pics: Prashant Ravi
The dense reserve is dotted with some 50 varieties of trees, environment-friendly buildings with bamboo and waste paper roofs, ponds, a solar energy-powered office, and a compost making unit.
All of this is the labour of love of a few thousand children from a little more than 100 schools in a city where lawlessness is rife and children have been kidnapped in the past for ransom.
Abhishek Bharadwaj, 15, Achala Parmar, 14, and Wartika Pande, 13, are among the school children who have been planting trees and greening a city where, by one estimate, there is only one tree for every 2,000 people.
"There is so much pollution in Patna. We thought that if people around us are not doing things to clean things up, we should take it up and do something about it," says Achala, daughter of a doctor father and homemaker mother.
By all accounts, the green warriors of Taru Mitra have achieved quite a lot.
Apart from creating a green lung, they have cleaned up large tracts of the city's grimy streets, cleared pig sties and set up some 25 small gardens. They have also set up eight nurseries, which sell plants at half the market price to students.
That is not all.
They have run a successful campaign against truckers who create sand pollution that chokes the city. These trucks typically pick up sand for building construction from the banks of the River Ganges nearby and carry it all over the city with no cover to keep the load contained.
For many years, the children have been stopping vehicles to do pollution checks. They gave out 2,500 pollution under control certificates last year alone in the city, after authorities gave them the nod.
They have travelled to the town of Hazaribagh and cleaned up the place after goading the local people to join them.
Back home in Patna, they have used pitcher irrigation - earthen pitchers buried to their neck in the soil and filled with water which seeps through its pores - to grow plants.
The indefatigable green teen brigade have even shamed local litterbugs by handing them on-the-spot fines of two rupees at the annual 10-day-long city book fair.
"Sometimes, people refuse to pay children," says Achala. "But our smiles work in the end."
Their work has earned the plaudits of environmental groups and the United Nations. The three children have travelled abroad to spread the good word and present papers at international conferences.
Most of the volunteers decided to become activists after watching their city become a veritable dumping ground.
"When I went to my native village and saw the blue sky and breathed the clean air, I realised how polluted my city was," says Waritika.
It has not been easy to put environment on the agenda in a city plagued by utter official inefficiency, soaring crime and massive corruption.
The bio reserve is an oasis of green in polluted Patna
In 1993, a Taru Mitra volunteer - a 21-year-old boy - died after a drunken man shot at him during a fair in the city.
But the spirit of the movement never died, and with time, Taru Mitra has become a model of proactive movement by children to improve the environment. It has spawned branches in other parts of the country.
None of the children wants to lose touch with their mission after they move on in life. Abhishek, who wants to go to management school, is even dreaming up a bio-reserve in the arid northern Indian state of Rajasthan some day and says he has already prepared a blueprint.
"It's all in our hands," says Abhishek with quiet flourish. "We have to create armies of nature lovers and mend the rot."