More than 70% of companies checked by Chinese authorities failed environmental standards during the latest round of air pollution inspections, state media reported on Sunday.

The findings came after two months of inspections across 28 cities in the notoriously smoggy Beijing-Tianjin-Hebei region and other nearby areas, the official Xinhua news agency said.

The inspections found 13,785 companies – or 70.6 per cent of those inspected – violated standards, with problems ranging from excessive emissions to insufficient pollution control equipment.

The government has thrown its weight behind an ambitious Jing-jin-ji plan to integrate the three neighboring cities, in part to alleviate the strain on the capital, Beijing, and relocate heavy industry away from major population hubs.