BEIJING, June 18 (Xinhua) -- China's imports of solid waste dropped significantly in the first quarter of this year as the government steps up enforcement of a ban on solid waste imports.

There was a 57-percent year-on-year decline in the amount of solid waste imports in the first three months, and 64 percent for restricted categories, according to the Ministry of Ecology and Environment. The figures increased from 9.2 percent and 12 percent last year, respectively.

The ministry said it will step up scrutiny over import licenses and crack down on violations of environmental protection laws by waste processing factories, striving to maintain the downturn in waste imports.

China began importing solid waste as a source of raw materials in the 1980s, and has for years been the world's largest importer, despite its weak capacity in garbage disposal. Some companies illegally bring foreign garbage into the country for profit, posing a threat to the environment and public health.

Given rising public awareness and a green development drive, the government decided last year to phase out and completely halt such imports by end of 2019, except for those containing resources that are not substitutable.

China's customs authority seized 137,000 tonnes of illegal trash imports last month in what it called the largest campaign against trash smuggling in recent years.

Li Ganjie, Minister of Ecology and Environment, said the ban on foreign rubbish is a major step to improve the environment, safeguard national ecological security and follow the green development strategy.