From January to late June, the number of crimes in Northwest China's Xinjiang Uygur autonomous region dropped by about 20 percent compared to the same period last year, the regional police department has announced.

Police across the region handled more than 30,000 crimes during the period.

The number of robbery cases dropped by 60.96 percent, the biggest decrease in any crime category, according to a statement issued by the regional public security department on Tuesday.

In Urumqi, which was struck by a riot on July 5 last year, the number of serious criminal cases tumbled by 58.9 percent over the same period a year ago, the statement said.

Eight types of offenses, including murder, abduction, rape and robbery, are defined in China as serious crimes.

Across Xinjiang, the number of serious criminal cases plunged nearly 40 percent.

The police said they caught suspects in 76.6 percent of these cases, without detailing the number of the cases.

During the same period, police in Xinjiang handled about 40,000 minor public security cases, down 12.6 percent year on year.

Huang Lixin, a guard working at a commercial property called Tianji Tower in downtown Urumqi, said he believes the social order in the city had improved substantially over the past year.

"Now I can see many policemen, armed police officers and security guards in the street or on buses, " he said.

The build-up to the forces patrolling in public spaces, crackdowns on various types of crimes and the establishment of emergency plans at all levels of police departments have resulted in the sharp drop in criminal cases in Xinjiang, according to the police statement.

Meanwhile, as the one year anniversary of the Urumqi riot draws near, local authorities have stepped up efforts to boost social order.

On June 20, the police in the city launched a 30-day crackdown on pickpocketing and extortion in public places, as well as in crime-prone blocks, according to the public security bureau of Urumqi.

The anti-criminal campaign is also aimed at preventing and reducing legal offenses by beefing up police forces and adjusting patrolling routes.