INDIA • Even air pollution can yield something positive, such as art. Just ask Graviky Labs, a Bengaluru-based start-up which has come up with an innovative method to trap soot from vehicles and transform it into ink.

The team of industrial and automobile engineers, computer scientists and design enthusiasts developed a proprietary, retrofit device called Kaalink, which can be attached to a vehicle's tail pipe to filter out residual soot.

This is then chemically processed and turned into a purified carbon pigment that in turn becomes Air-Ink.

The unit captures 95 per cent of the particulate matter emanating from the engine without inducing back-pressure in the vehicle. Designed to work on Indian roads and fitted with heat and waterproof electronics and materials, Kaalink is undergoing certification and is being tested in several pilot demonstrations.

Graviky Labs said its products aim to turn the darkness of pollution into bold strokes.

The range includes marker pens with tips of various thicknesses, which contain from 40 to 130 minutes of captured diesel car pollution. In the future, the "art from pollution" series will include oil-based paints, fabric paints and outdoor paints.

Soot is mostly made up of fine black particles 2.5 micrometres or less in diameter and carbon produced by incomplete combustion of fossil fuels.

The problem of fine particulates is growing universally. A Greenpeace report released earlier this year showed that 90 per cent of Indian cities studied had pollution levels over prescribed standards.

The capital New Delhi was found to be the most polluted city, with the annual average for PM10 being 268 micrograms per cubic m, which is more than four times the 60 micrograms/cubic m limit prescribed in the National Ambient Air Quality Standards of the Central Pollution Control Board.

Thanks to a successful Kickstarter funding campaign, the aim is to "scale up and make Air-Ink more widely accessible", the company said in a statement.

Graviky Labs claims to have cleaned 1.6 trillion litres of outdoor air so far.