Generate an explanation for the given claim using the provided supporting material from the paragraph. Please consider the following points while generating an output. 1) The claim will always have supporting proof in the paragraph, and the paragraph will have a clear point of view supporting the claim. 2) There can be instances where direct correlation to the claim is not available. Make use of the sentences in the paragraph to provide a corresponding output supporting the claim. 3) The explanation should be at least one and at most twelve sentences long.
Q: Paragraph: Chinese Premier Li Keqiang declared a "war on pollution" in 2014 and the government has spent billions of yuan to bolster monitoring and enforcement, raised industrial standards and shut thousands of small "backward" enterprises. But Reuters calculations based on online monitoring data show 30 out of 39 cities in the key northern pollution control zones of Beijing-Tianjin-Hebei and the Fenwei Plain failed to meet air quality targets over the autumn-winter period to end-March, despite imposing special restrictions. The Ministry of Ecology and Environment (MEE) did not immediately respond to a request for comment on Monday, but it has already warned that momentum had slowed as a result of a slowing economy in some regions. The cities were under pressure to cut concentrations of hazardous airborne particles known as PM2.5 by around 3 percent year on year, with some targeted to make bigger reductions. Official data shows big improvements in air quality in March, with average PM2.5 readings falling 29 percent to an average of 52 micrograms per cubic meter in the 39 cities. But over the six-month period, concentrations rose 6 percent to 82 micrograms, more than double the national standard of 35 micrograms. PM2.5 actually increased in 24 cities, with central China's Henan province performing especially badly. The Henan steel city of Anyang was the worst performer, with PM2.5 rising 27 percent to 111 micrograms. Residents blamed the weather and the city's position downwind from large steel bases in neighboring Hebei province. "The key thing is that Anyang has the strictest pollution controls of all ... but it ranks the worst for air quality," Li Xianzhong, co-owner of the privately-owned Xinyuan Iron and Steel Corporation, told Reuters. The capital Beijing was one of eight cities to meet its targets. It was ordered only to "improve" from last year and saw average PM2.5 fall by 3 percent, thanks to a cut of 39 percent in March. The environment ministry has vowed not to relent in fighting pollution and will implement special restrictions from October. It also said it would not tolerate attempts by local governments to blame slowing growth on tougher environmental rules. But in a sign China was trying to avoid economic disruptions, ministry spokesman Liu Youbin told a briefing last week that China would not allow overzealous officials to shut large swathes of industry. "We will resolutely oppose anyone using environmental protection as an excuse to perform simplistic and crude actions such as the emergency closure of business operations," he said. Claim: Most northern China cities fail to meet winter smog targets: data.
A:
A majority of 39 northern Chinese cities have failed to meet anti-pollution targets over the six-months to end-March, a Reuters study of official data showed, adding to fears the war on smog has lost momentum.