Hong Kong: Tens of thousands of people will be able to cross freely from either side of Hong Kong's border with mainland China every day starting Sunday, according to the city's leader. Under China's "zero-COVID" strategy, in which entry into the country is limited, infected people are isolated, and areas with outbreaks are sealed off, the city's land and sea borders with the mainland The checkpoints have been closed for almost three years. The reopening is projected to provide a much-needed boost to Hong Kong's economy. Thursday's announcement coincided with China relaxing some of the world's strictest anti-virus rules. China will gradually increase the number of flights between Hong Kong and the mainland starting Sunday and end restrictions on the number of passengers flying. Also Read: Due to drug-related police, the Philippine police chief has offered to resign Passengers will not have to undergo quarantine upon arrival on the mainland, Chief Executive John Lee announced at a news conference. According to Li, four border checkpoints that have been closed for nearly three years will be reopened as part of the first phase of the reopening, bringing the total number of operational checkpoints in the city to seven. In Hong Kong, all checkpoints are currently closed, except for three. Lee said that after discussing the situation with mainland authorities, the Hong Kong government will decide when to expand the scope of reopening the border. Also Read: Death of Ruslan Khasbulatov leader of Russian parliament uprising A quota system allows up to 60,000 people to leave Hong Kong for mainland China per day. The number of people entering the city from the north is also subject to the same cap. To reserve a quota slot, passengers must register online and receive a negative COVID-19 test result within 48 hours of departure. Southeast China's Guangdong province borders the Chinese territory of Hong Kong, which is semi-autonomous. People have to cross immigration to move between the two. Since 2020, border restrictions have severely hurt the city's economy, especially the tourism industry. Starting Sunday, the mainland will also wind down requiring visitors to be quarantined, an important step toward fully reopening international travel. Also Read: On Independence Day the head of Myanmar's army promotes its election strategy According to the mainland city's capacity and the epidemic situation, Chinese citizens will be allowed to travel to Hong Kong for sightseeing in a gradual and orderly manner.