For the fourth year in a row, all reported robberies were solved before the end of the year, Shanghai police said of their work results for 2021 on Friday.

Last year, over 96 percent of all burglary cases reported in the city were solved, and in nine of 16 Shanghai districts all such cases reported were solved, police said.

As of the end of 2021, smart security devices had been installed in all residential complexes and office buildings in Shanghai, they said.

These contributed to a huge drop in the number of burglary cases reported around the city, according to police.

In Changning District, no burglary case was reported in 99 percent of residential complexes, police said.

Meanwhile, thefts reported from the city's Metro system last year dropped 77.2 percent from the previous year, and all cases were solved, police said.

At Shanghai Railway Station and People's Square Station, where thefts used to happen more often than elsewhere, only six were reported last year, a drop of 80 percent from the previous year, according to police.