Thai Prime Minister Prayut Chan-o-cha on Tuesday visited the northern city of Chiang Mai, which is currently battling the worst air pollution in the world.

‘The government will try to tackle this within seven days,’ Prayut said, while discussing ways to alleviate the problem with local officials.

The situation has been so bad in the popular tourist destination that King Maha Vajiralongkorn also expressed concern and instructed authorities to tackle the smog as soon as possible, Prayut said.

According to website airvisual.com, Chiang Mai has been ranked the city with the most polluted air in the world for over a week, with the Air Quality Index (AQI) measuring at 409 points on Tuesday, considered to be at the ‘hazardous level’.

Photos posted on social media showed very heavy smog in the northern region, with some users saying their visibility distance was only a few hundred metres and that they needed to remain indoors and move elsewhere until the situation improves.

‘I just order in and stay at home. But it's getting out of hand now,’ Chiang Mai resident Jignesh Davda told dpa.

Prominent travel blogger Richard Barrow tweeted that the pollution map ‘makes it look like Northern Thailand is on fire.’  ‘It would be stupid not to wear smog masks today,’ he wrote.

Environmental group Greenpeace and academics attribute the current haze to agricultural burning in the region and have urged authorities to strictly enforce environmental laws.