Many countries in Asia are currently dealing with the second wave of coronavirus and a growing number of cases. But not in Hong Kong. Thanks to strict measures and early controls, authorities in the city haven’t reported a single case for the first time in more than six weeks.

Hong Kong detected its first COVID-19 case on January 23 and suffered a spike in March when residents, many of them students, returned from high-risk areas such as Europe and North America. The number of cases actually tripled in a short period of time.

But the daily number of new cases has dwindled significantly since then and has remained in the single digits, all thanks to more strict measures. On Monday, the city saw no new infections at all. Hong Kong has recorded a total of 1,025 coronavirus cases so far, with four fatalities.

Gabriel Leung, the dean of medicine at Hong Kong University, told Fortune that the city is “the gold standard of infection control” and linked its success to early screening measures at ports, a robust health care system with sufficient isolation wards, extended school closures, and a society-wide adoption of face masks.

Arrivals from foreign countries were required to wear tracking bracelets and undergo two weeks quarantine upon arrival. As case numbers continued to climb, Hong Kong barred entry to all non-residents except those from Macau, Taiwan, and mainland China, and required all remaining arrivals to submit to mandatory testing.

Within Hong Kong, restrictions on movement also increased. During the last week of March, the government ordered all cinemas, theaters, arcades, and other entertainment venues to close. In the following weeks, bars, karaoke clubs, gyms, spas, and virtually all other service providers were shut down.

Police wielding measuring tapes have brought charges against dozens of rule-breaking eateries while 130 members of the public have been fined for breaking a rule that prohibits gathering in groups of more than four people. Quarantine breakers are facing stiff punishment, too: one man was sentenced to four weeks in prison.

While the second wave appears to have subsided, the Hong Kong government has decided against easing the restrictions that helped mitigate the infection’s spread. On Tuesday, Chief Executive Carrie Lam announced that the social distancing rules, many of which were due to end this week, will be extended for another two weeks.

A spokesperson for the Centre for Health Protection urged the public to remain vigilant: “Given that the situation of Covid-19 infection remains severe and that there is a continuous increase in the number of cases reported around the world, members of the public are strongly urged to avoid all non-essential travel outside Hong Kong.”

The situation in Hong Kong is very different from those in Singapore and Japan. Both countries had been praised for their initial efforts but then saw a spike in the number of cases. In Singapore, the surge was linked to the government overlooking the living conditions of foreign workers, while Japan deals with a collapse of its health system.