Delhi is one of the world's most polluted cities and there has been much head-scratching about what can be done to tackle the problem.
A lot has already been done; the city's bus fleet has been converted to compressed natural gas, the courts have begun to tax large diesel SUVs, but the city seems to get dirtier every year.
Tarun Sebastian Nanda, a 35-year-old UK citizen of Indian and Dutch parentage, has decided to take an alternate route. Rather than going large scale, he has decided to take small steps to fight pollution in the city.
An environmental engineer, Nanda has begun to clean the city's water bodies with home-made, floating "islands". (Like the air, much of the city's water is in poor condition too. A report by the Delhi government's Department of Environment says 107 of the city's 1,012 water bodies are untraceable.)
This is what Nanda does:
He collects old PVC drainpipes and cuts them up. After inserting plastic bottles into the pipes to keep them buoyant, Tarun then ties them up to make a frame out of the pipes.
The next step is to wrap the frame in a mesh and stuff it with coir fibre. Aquatic plants are planted into this before the island is placed in the water.
Nanda says one of his islands can be put together for less than Rs 4,000.
The "islands", which can be carried by two people, are then placed in a water body.
The plants take the nutrients from water and use them to grow. The roots act like as a filter to block suspended solids. They also act as a place for microorganisms to live, which in turn break down the pollutants, converting nitrates and phosphates into biomass.
Nanda has so far made about 50 of the islands -- the idea wasn't his own; Nanda says this is an established engineering practice around the world. He dropped them in the wetlands of south Delhi’s Vasant Kunj and Vasant Vihar.
Did they work?
“The very fact that the plants are growing is evidence that they are working," says Nanda.
Although one can start seeing the results within a month when the plants grow, it will take nearly six months before the water samples are tested for the pollution levels.
Nanda also notes that pollution levels will not come down significantly unless at least half of the water body is covered with the islands.
The next step, says Nanda, is to take the idea around the country.
To begin with, he plans on holding workshops in Delhi to train people on how to make his islands.
But it's been tough dealing with bureaucracy in the city's municipalities.
"I'm hoping that as public get more involved, the govt also gets more involved and they'll give me permission to do this officially. My intention is to do it with or without official permission. There's no reason why these water bodies exist like this," he says.
How to make your island
- 1-litre plastic bottles (about 25 of them)
- HDPE piping (7 metres)
- Roll of plastic mesh (available in wholesale markets)