Beijing police on Friday set fire to 274.6 kg of illegal drugs seized from 2010 to 2011.

The banned substances were thrown into an industrial furnace in the suburban Changping district on Friday.

The majority of the substances destroyed included heroin, methamphetamine and marijuana.

According to police, seized drugs are usually kept for two years as evidence of criminal cases before they are destroyed.

As of May, Beijing police uncovered more than 680 cases of drug trafficking, captured more than 720 suspected dealers and seized more than 60 kg of illegal drugs, a rise of 78.5 percent year-on-year, according to police.

In March, police made the capital city's largest drug trafficking bust in the last decade, capturing 15 suspects and confiscating a total of 15 kg of illegal drugs, said Yi Yang, deputy head of the anti-drug department of Beijing police.