Severe air pollution in Chiang Mai, Thailand has led to the local fire service using robots to spray water around the city.

Video shows a forest fire raging on the city's outskirts and the remote-controlled LUF 60 robot being deployed to spray water.

On Tuesday, the city received the most unwanted accolade of being the most polluted on the planet, according to the Bangkok Post.

The IQ AirVisual air monitoring website said the city had the worst air quality in the world for several days running, with a USAQI of 195, followed by Beijing on 182.

USAQI is an air quality index used by the US Environmental Protection Agency, the Bangkok Post noted.

Some 30,000 people have had to go to hospital because of respiratory illnesses over the last three months, it added.

According to the National newspaper in Abu Dhabi, where it has also been deployed, the robot is fitted with a 140 horse-power diesel engine and can travel up to 300 metres.

It can spray up to 2,400 litres of water a minute to the source from a distance of 60 metres, it added. The robot can also perform sharp turns, climb stairs and remove obstacles.

Severe air pollution in Chiang Mai has the Fire Service spraying water around the city

A forest fire rages outside Chiang Mai, Thailand. The city is near the top of the world list for unhealthiest air quality,recently reaching hazardous levels of PM 2.5 particles.

The Fire Department is spraying water around the city using remote controlled vehicles made in Austria, called LUF 60. They started using them five years ago when air pollution was also bad.