China is to introduce tough controls on ship emissions at three key port areas from January to reduce the sulfur dioxide that results in acid rain, causing respiratory difficulties and sometimes premature death, the Ministry of Transport said yesterday.

If strictly implemented, the move would force oil suppliers to increase the supply of cleaner marine fuel, according to industry experts. The ministry gave no details on how the new emissions rules would be enforced or the penalties for non-compliance.

The new rules will apply to merchant ships navigating or anchoring in the waters of the Pearl River Delta, Yangtze River Delta and the Bohai Bay rim, with a goal to cut sulfur dioxide by 65 percent by 2020 from the 2015 level, according to a document issued by the ministry.

Similar emissions control areas exist in the North Sea and the North American coast.

Ships berthed at ports within the three Chinese emissions control zones will start using bunker fuel with a maximum sulfur dioxide content of 0.5 percent from January, the ministry said.

Hong Kong made it mandatory in July for merchant ships to switch to fuel with a SO2 content of 0.5 percent from high sulfur fuel. Neighboring Shenzhen launched a voluntary fuel switching scheme in July that is expected to cost 200 million yuan (US$31 million) in subsidies over three years.

Enforcement of the new measures will initially be up to individual ports, but the controls will be toughened in 2017 to cover all key ports in the three control areas.

They will be tightened further from the start of 2019, when ships entering control zones, not just berthed or anchored, will have to use 0.5 percent SO2 bunker fuel or below. Fishing, sports and military vessels will be exempt, the ministry said.

Oil consultancy ICIS estimated that the majority of fuel in use by China’s shipping sector has 1-2 percent SO2 content.

The International Maritime Organization, a UN body which regulates merchant shipping, plans to introduce a global cap on ship emissions in either 2020 or 2025.

It will carry out a review in 2018 that will include an assessment of the availability of low-sulfur fuel that will be used to decide the actual implementation date.