Organisers of New Delhi's half-marathon race have used ultra high frequency (UHF) radio waves to clear the air for runners in the hope that it could improve the city's air quality.

Key points: The UHF waves dispel pollution from a tiny particulate that can damage the lungs

The UHF waves dispel pollution from a tiny particulate that can damage the lungs This year's race was moved one month before firecrackers are set off for Diwali

This year's race was moved one month before firecrackers are set off for Diwali India is home to the world's 14 most polluted cities

The technique was among several measures event organisers took to reduce the threat of toxic smog to the race's 35,000 participants on Sunday (local time).

Medical experts last year urged the cancelling of the 2017 race as the capital and a large part of northern India were blanketed by smog, partly caused by the smoke from burning crop waste and thousands of firecrackers.

Marathon organisers responded by bringing the date of this year's race forward to October, away from November's Diwali festival when the firecrackers are set off.

They also tried to dampen down the dust that hangs over the city in winter, including reagents from the mining industry to treat roads, dropping water vapour along the course from a height of just over 6 metres.

The UHF waves that were used on Sunday dispel pollution from particulate matter measuring only 2.5 microns, known as PM2.5.

PM2.5 is about 30 times smaller than a human hair, which allows it to lodge deep in the lungs, damaging the respiratory system.

The race promoter said there were no pollution-related incidents among the 35,000 runners. ( Reuters: Anushree Fadnavis )

Managing director of race promoter Procam International, Vivek Singh, told Reuters the measures reduced pollution by "at least" 30 per cent during the race, though air quality at monitoring stations near the route were still rated as "very unhealthy" under international standards.

"It was a great day with clear skies and no pollution-related incidents among our 35,000 runners," Mr Singh said.

Mr Singh said the Delhi government, which last year resorted to shutting power stations and banning some cars from roads to clear the air, should look at using the UHF technology, manufactured by a Bangalore-based company Devic Earth, to mitigate pollution.

"We have shown that it works and made a point to tell the authorities," he added.

India is home to the world's 14 most polluted cities.

First-time competitor and carbon market analyst Emily Jackson said: "I did doubt signing up, but it was just the usual morning haze, and didn't feel hard to run in."

The women's race was won by Ethiopian Tsehay Gemechu in a course-record time of one hour, six minutes and 50 seconds, while teenage compatriot Andamalak Belihu finished first in the men's race with a time of 59 minutes and 18 seconds.

Reuters