SHANGHAI (Reuters) - Air pollution in a key Chinese region surrounding Beijing worsened in the first four months of this year, despite tough new campaigns to enforce green regulations and punish offenders, official data published on Tuesday showed.

Vehicles drive on the Fourth Ring Road during the smog in Beijing, China, February 14, 2017. REUTERS/Jason Lee

In the Beijing-Tianjin-Hebei region, average concentrations of small breathable particles known as PM2.5 rose nearly 20 percent year-on-year to 85 micrograms per cubic meter from January to April, said the Ministry of Environmental Protection.

China has launched campaigns aimed at ensuring the region meets a series of politically significant 2017 air pollution targets set by the central government in 2013.

The region is under pressure to cut 2012 levels of small particulate matter by around 25 percent by the end of this year, with the capital Beijing aiming to keep average PM2.5 rates at below 60 micrograms per cubic meter, down from 73 micrograms in 2016.

Beijing has already promised “extraordinary measures” to ensure the target is met, but its average PM2.5 reading stood at 76 micrograms in the first four months of 2017, up 11.8 percent from the same period of 2016.

There were improvements in April alone, with average PM2.5 readings in the region falling 5.2 percent to 55 micrograms, while the number for Beijing was 53 micrograms, down 22.1 percent.

But those were not enough to offset the outbreaks of near-record smog that hit the region in January, prompting dozens of cities to issue “red alerts” to curb industrial activity and thin traffic.

Chinese cities need to cut average PM2.5 readings to 35 micrograms in order to meet state standards, while the World Health Organization recommends concentrations of no more than 10 micrograms.

Hebei province accounted for six of China’s 10 smoggiest cities over the first four months of the year, with the steel city of Handan in the province’s south ranking the worst over the period.

The environment ministry said last month it would dispatch 5,600 inspectors to look into the sources of air pollution in 28 cities in and around the Beijing-Tianjin-Hebei region. Violations have been uncovered at more than two thirds of the firms that have been inspected.

Hebei, which produces more steel in a year than the whole of the European Union, admitted last week that it was still failing to implement policies aimed at curbing pollution and industrial overcapacity.