(Bloomberg) -- Thailand is weighing a ban on imports of corn from neighboring countries that practice agricultural burning, as the Southeast Asian nation steps up efforts to battle a chronic air pollution that’s hit some of its popular tourist spots.

Prime Minister Srettha Thavisin has asked the Commerce Ministry to issue a set of regulations to curb corn imports during the peak season of residual crop burning in neighboring countries. The restrictions will comply with the World Trade Organization rules and be in line with Thailand’s new Clean Air Act that’s set to be approved by lawmakers by the end of the year, he told reporters Tuesday after a cabinet meeting. 

Although Srettha did not identify the neighboring countries, the measure will likely hit imports from Myanmar, Laos and Cambodia. The three neighboring countries supply 1.5-1.8 million tons of corn to Thailand, which needs more than 8 million tons, mostly for livestock feed production, but produces only about 5 million tons domestically, according to customs data.

The move to target corn supplies came as popular tourist destination Chiang Mai was ranked among the world’s most-polluted cities over the past week as thousands of hotspots raged across Cambodia, Laos, Myanmar and Thailand. 

The country is in the middle of a harsh summer with the temperatures forecast to rise as high as 44.5C (112F) in some parts, the Thai Meteorological Department said last month. A combination of humidity, wind and other factors last year pushed the heat index to a record of above 50C in parts of the country, pushing electricity demand to the highest level ever.

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Apart from Chiang Mai, Bangkok and other Thai cities have also grappled with poor air quality in recent years, with pollution tending to get worse in the dry season around December to February due largely to crop burning in Thailand and neighboring countries and vehicular emission. Authorities have urged residents to work from home or wear respirators during heavily polluted periods. 

Last month, Thailand kicked off its so-called annual royal rainmaking program to induce artificial rain to battle air pollution and ease dry weather conditions in the main crop-growing areas. Last year, the government had urged the Association of Southeast Asian Nations to take steps to tackle trans-boundary haze that was blamed on hotspots across the region. 

Thailand, the world’s second-largest exporter of sugar, has also discouraged its farmers from burning their sugarcane fields — which removes unwanted parts of canes — before harvest and handed out premiums for those who deliver fresh canes.  

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