Chinese demand pushed Asian liquefied natural gas prices to a three-year high, as the country’s importers scramble for supplies in the face of Beijing’s move to reduce urban air pollution.

This year’s rally in spot prices of the super-cooled fuel has surprised market executives and analysts, who had long been expecting a subdued market due to extra supplies of LNG from new projects. However, delays in production and China’s “2+26” pro-gas policy, aimed at controlling pollution in Beijing, Tianjin and 26 other cities, has propelled demand.

The Asian spot LNG index Japan-Korea Marker from S&P Global Platts rose to $10.04 per million British thermal units on Thursday, the highest level since December 2014, and a fifth higher since the same time last year.