NEW DELHI - One of the world's most polluted capitals, New Delhi, closed a major stretch of a road to private cars for a few hours Thursday, hoping to give its citizens a brief breath of fresh air by observing a car-free day.

Only public transport was allowed on the road from Old Delhi to the doorstep of Parliament.

The city's top elected official, Arvind Kejriwal and his cabinet colleagues, led hundreds of cyclists as they pedaled the route to encourage people to use public transport.

"All of us have to do our bit to decongest the roads and to reduce pollution. People should leave their cars and start using public transport and bicycles," Kejriwal said as he prepared to lead the cyclists.

Although the event covered only a six-kilometre stretch, many people hailed the government's effort as a first step to clean the city's heavily polluted air.

"Even though it's only for a few hours, it's a very good start. We have to get people thinking about the harm air pollution is doing to our health," said Sunil Kumar, an environmental activist who cycled to the event.

Others said closing just one road for five hours would not make a dent in the heavy, particulate-ridden air in the capital.

Traffic was sparse in the rest of the city Thursday morning on account of the Hindu festival of Dussehra. Schools, colleges, businesses and government offices were closed and most people stayed home.

Air pollution kills millions of people every year, including more than 627,000 in India, according to the World Health Organization.