Flood-affected residents of Beicheying Village, Qinglonghu Township line up to receive relief foodstuffs in Fangshan District, a suburb of Beijing, capital of China, July 26, 2012.[Photo/Xinhua]

Beijing's top official said Friday the disastrous rainstorm exposed many loopholes in urban planning, construction, infrastructure and emergency management.

Guo Jinlong, secretary of the Communist Party of China (CPC) Beijing Municipal Committee, mourned the people who lost their lives in the disaster during a field trip to Fangshan District, which was worst hit by the rainstorm.

"We must seriously reflect on the lessons and always bear them in mind," Guo said.

At least 77 people were killed in the downpour on July 21, latest available official statistics showed.