MUMBAI, Nov. 18 -- Ghatkopar residents Shivani Khot, 20, and her sister, Esha, 15, have come up with a unique solution to curb air pollution and conserve fuel - a blue traffic light, which will blink 10 seconds after the red light comes on and stop blinking 10 seconds before the red light goes off. During this period, drivers will have to switch off their engine.

Vehicular idling is a phenomenon where drivers unnecessarily keep their engine switched on. This leads to emission of half-combusted gases such as particulate matter and nitrogen dioxide that are harmful to human health. "In the absence of directives, citizens are not fully aware of idling and its ill effects," said Esha. "In metropolitan cities, long-duration traffic signals are ...