SHANGHAI (Reuters) – China’s environment ministry warned that unfavorable weather could raise the risks of smog over autumn and winter, and it vowed to improve its emergency response times to ensure 2017 air quality targets are met.

In a notice posted on its website on Sunday, the Ministry of Environmental Protection (MEP) said its weather forecast for autumn and winter was “not optimistic”.

The Chinese government has staked its reputation on winning a “war on pollution” launched in 2014 in a bid to reverse the damage done to its skies, rivers and soil and head off public anger about the health impact of smog.

The U.S.-based Health Effects Institute (HEI) linked air pollution to 1.1 millions deaths in China in 2015.

Last month, the ministry said it would intensify its pollution crackdown in 28 smog-prone cities in northern China over winter in a bid to meet politically crucial targets for the year.

It promised to cut monthly average concentrations of small, breathable particles known as PM2.5 by at least 15 percent from October to March, with the capital Beijing and the port city of Tianjin aiming for 25 percent reductions.

But higher rates of melting in the Arctic icecap, combined with Pacific Ocean warming, are expected to result in weaker than usual high-pressure cold fronts heading south into China from Siberia, the ministry said, meaning weather conditions are likely to be warmer and more humid than usual.

It said it would work to improve alerting systems and speed up the implementation of emergency emission reduction measures. It also promised to boost its forecasting capabilities to 10 days from the current seven.

“Heavy pollution has become a concern that reaches the heart and lungs of the Chinese public, and the Ministry of Environmental Protection will go all out to make it a top priority,” it said.

The Beijing-Tianjin-Hebei region vowed in 2013 to cut average PM2.5 concentrations by 25 percent by 2017.

But smog readings spiked to near record levels in January and February, meaning that PM2.5 in the region rose in the first seven months of the year.

PM2.5 in Beijing hit 64 micrograms per cubic meter in the first seven months, down 1.5 percent on the year but higher than its 2017 target of less than 60 micrograms.

The government blamed the smog surge at the start of 2017 on “unfavorable weather conditions”, and officials said the winter deterioration should not overshadow the genuine progress made in the “war on pollution”.

“While overall air quality in Beijing-Tianjin-Hebei and surrounding areas has continued to improve, improvements during winter have not been significant,” the ministry said on Sunday.