China's stringent approach to control the spread of COVID-19 has worked, as no new locally transmitted cases were reported on Monday for the first time since July, U.S. network CNN reported on Monday.

China on Monday reported 21 imported COVID-19 cases, and zero locally transmitted symptomatic infections for the first time since a major outbreak of the highly-contagious Delta variant in the country last month.

On July 20, a cluster of COVID-19 cases were detected among airport cleaning staff in the eastern city of Nanjing and have since spread to more than half of China's 31 provinces, infecting more than 1,200 people.

The fresh outbreak was seen as the biggest challenge yet to the country, which has a zero-tolerance policy to the virus.

Chinese authorities responded by imposing targeted lockdowns, conducting massive testing and tracing campaigns and tightening travel restrictions.

Over the past week, the country saw daily infections falling steadily into single digits.

"The strict measures appeared to be working," said CNN, noting that "China could become first country to control Delta outbreak."

Worldwide COVID-19 outbreaks, driven by the spread of Delta variant in recent months, have prompted other countries that sought to completely eradicate COVID-19 within their borders, like Australia, to rethink their approach.

The network added that for more than a year, these measures in China had been "largely successful in keeping cases close to zero." 

The Chinese mainland reported 20 new confirmed COVID-19 cases on Tuesday, including four local transmissions, according to the National Health Commission.