Women boxers training for world championships starting in New Delhi this week are wearing surgical masks, scarves and even T-shirts across their mouths as the level of air pollution in Delhi rises several times beyond the safe limit. The AIBA Women's World Boxing Championships is taking place in an indoor stadium from Thursday through to November 24 but teams are complaining about a toxic smog hanging over the city, caused by seasonal burning of crop stubble and emissions from vehicles and industry.

The weather, with no wind to blow the pollution away, has aggravated the problem in one of the world's most polluted cities.

"My family is worried. We know it is not good for our body," said 27-year old Bulgarian Stanimira Petrova, a gold-medallist in the bantamweight category in the championships in 2014.

"It's difficult. I wear a scarf but I have to get accustomed."

On Tuesday, the level of deadly particulate matter PM 2.5 that lodge deep in the lungs was at 403, about eight times the safe limit, according to a reading by the pollution control board.

Authorities have banned the entry of heavy vehicles into the city and ordered construction work to stop and sprinklers to keep down the dust. But the air quality remains in the severe zone.

Seven European boxers whom Reuters spoke to complained that the air left a bad taste and irritated their eyes.

Their coaches said they were advised about the poor air but organisers had not given them any protective gear.

Indian Olympic flyweight bronze medallist MC Mary Kom is among those taking part.

French coach Anthony Veniant said he had asked for the tournament to be moved out of Delhi but his request was turned down.

"We feel the air is no good. Some of the parents of these players are worried and we tell our players to restrict their time outside," Veniant said.

Prolonged exposure to high levels of PM 2.5 and PM 10, another pollutant, leads to respiratory illnesses. Doctors in Delhi have reported an increase in the number of patients with respiratory problems.

Jay Kowli, secretary general of the Boxing Federation of India, said the air quality was being monitored in training arenas, boxing venues and the hotel where the athletes are staying.

He ruled out any change of location.

"Shifting the venue is impossible. Delhi has the best sports facilities in the country," Kowli said.

Teams have been hard at training this week.

Daniel Nash, the coach for the Swedish team, said pollution was a problem, but he had asked the boxers to focus on the competition.

Promoted

"I'm telling my players to not let this issue affect their game," Nash said.

Contestants just have to deal with it, said Abdul Fkiri, the coach of the Dutch team.