BEIJING, April 4 (Xinhua) -- China's exit and entry administration has ordered border inspection agencies to open all customs clearance channels to ensure smooth entry and exit of tomb sweepers from Hong Kong and Macao special administrative regions as well as Taiwan.

The agencies in Shenzhen, Zhuhai, Guangzhou and Xiamen should make every effort to improve efficiency, cut waiting time and prevent congestion during the upcoming Tomb-sweeping Day, said the administration Wednesday in a statement.

The administration also called on the agencies to coordinate with their counterparts in Hong Kong and Macao.

Qingming Festival, known in English as Tomb-sweeping Day, falls on April 5 this year. A large number of people from Hong Kong, Macao and Taiwan return to the mainland each year to pay tribute to ancestors, deceased friends and other family members during the festival.

It is estimated that more than 2.4 million people will pass cross the Shenzhen - Hong Kong frontier between April 5 and 7, up 13 percent from last year, while those through Zhuhai - Macao will exceed 1.4 million, an increase of 5 percent.