BEIJING'S POLLUTION WINNINGS

A four-year effort yields better air quality that could extend life expectancy.

ON March 3, 2014 the Chinese premier, Li Keqiang told almost 3,000 delegates at the National People's Congress and many more watching live on state television:

''We will resolutely declare war against pollution as we declared war against poverty.''

The statement broke from the country's longstanding policy of putting economic growth over environment, and many wondered whether China would follow through.

Four years after that declaration, the data is in:

China is winning, at a record pace. In particular cities have cut concentrations of fine particulates in the air by 32 percent on average, in just those four years.

The speed of the antipollution drive has raised important questions about its human costs.

But if china sustains these reductions, recent research shows and indicates that residents will see  significant improvements to their health, extending their life spans by months or years.

How did China get here?

In the months before the premier's speech, the country released a national air quality action plan that required all urban areas to reduce concentrations of fine particulate matter pollution by at least 10 percent, more in some cities.

The Beijing area was required to reduce pollution by 25 percent, and the city set aside an astounding $120 billion for this purpose.

To reach these targets, China prohibited new and coal-fired power plants in the country's most polluted regions, including the Beijing area.

Existing plants were told to reduce their emissions. If they didn't, the coal was replaced with natural gas.

Large cities, including Beijing, shanghai and Guangzhou, restricted the number of cars on the road.

The country also reduced its iron-and-steel making capacity and shutdown coal mines.

Some of the actions went from aggressive to extraordinary.