Why were Hong Kong fans booing their anthem?

The Hong Kong Football Association (HKFA) has been fined $40,000 Hong Kong dollars ($5,160; £3,400) by Fifa after its fans booed the Chinese national anthem during a match last month.

An object was also thrown onto the pitch during the World Cup qualifier against Qatar.

Fifa, football's governing body, previously warned the HKFA over booing.

The anthem has been shared by Hong Kong and mainland China since the former returned to Beijing's control in 1997.

Video production: Ed Ram