* New targets tougher than those in current 5-yr plan
* China has been fighting to clear its notoriously polluted air
* Minister says new goals still being worked out
* Govt plans nationwide inspections this year
* MEP will become Ministry of Ecological Environment in latest reform
BEIJING, March 17 (Reuters) - China will set more stringent targets for improving the nation's air quality under a new three-year plan, as Beijing prepares to beef up a nationwide crackdown on polluters in its years-long campaign to clear its notoriously toxic skies.
The new targets for concentrations of small, breathable particles known as PM2.5 will be lower than those in the country's current five-year plan that was due to end in 2020, environment minister Li Ganjie said at a briefing on the sidelines of the country's annual Parliament on Saturday.
In January, the Ministry of Environmental Protection (MEP) said it was drawing up plans for tougher curbs on smog during the next three years to 2020 after a five-year crackdown on pollution helped it attain air quality targets in December.
Li declined to give further details of the new goals as they are still being worked out.
By the end of 2017, the country had already cut PM2.5 concentrations by around 15.8 percent, not far from the target of reducing average levels for cities by 18 percent by 2020.
"So we will set a lower target for the new three-year plan," he said.
The government will also set up a nationwide inspection system this year, which will give responsibility for regular checks on polluting companies and factories to local authorities, in addition to central government, he said.
The government will also punish local authorities who do not enforce the regulations correctly, he said. In some regions last year, regional governments issued blanket orders for companies to close even if they complied with tough emissions rules, he added.
The "one size fits all" strategy by some local authorities will not be tolerated, he said.
His comments come after the government announced this week the 10-year old MEP will be transformed into a more powerful Ministry of Ecological Environment, absorbing duties overseeing river, marine and soil pollution as well as climate change held by other ministries and departments.
It was announced as part of the biggest shake-up of government in years.
Li said the bigger ministry would help push environmental protection, which is a hot-button social and economic issue for the world's No. 2 economy, but he did not give any other details.
The chief of the new ministry is expected to be announced this week.
(Reporting by Muyu Xu and Josephine Mason Editing by Joseph Radford)