KUNMING -- Police in China's southwestern province of Yunnan seized 23.3 tonnes of illegal narcotics in 2015, the police authority said Sunday.

Police in the border province cracked down on 22,000 drug cases and local rehab centers took in over 67,000 drug users in 2015, according to the public security department of Yunnan.

Last year marked the end of the province's five-year campaign against drug crime.

Yunnan is among the Chinese regions most affected by drug use, due to its proximity to the opium-growing Golden Triangle in neighboring Southeast Asian countries. It is also a source of domestic drugs.