Authorities of Putian, a city of 3.2 million in the coastal Fujian province of China’s Southeast, have begun to impose measures to curb an outbreak of the Delta variant of COVID-19 which is thought to have emanated from a primary school in Putian. The measures imposed include travel restrictions and school closures.

The city authorities have ordered the testing of all residents on Tuesday which comes after certain cases were linked to a returnee from Singapore. Upon his arrival into the city, over 100 people have been infected, resulting in a province-wide outbreak.

According to the National Health Commission, 59 new locally transmitted cases were reported on September 13, 37 new cases up from 22 infections recorded on September 12 and all the cases were in Fujian.

A total of 102 community cases, in four days, have been reported in three Fujian cities, including Xiamen, which has a population of five million.

The outbreak has been connected to the parent of a child at the Putou Primary School who had returned to China from Singapore in August and had completed quarantine and had several Covid 19 tests done, before testing positive this month after developing symptoms.

A 12-year-old boy, who was the man’s son and a classmate were among the first patients detected in the cluster last week, after which the variant then spread through the classrooms, infecting more than 36 children, in the first big school-linked spread the country has seen since the start of the pandemic, while the second cluster of cases is linked to a shoe factory.

This comes ahead of China’s National Day on October 1st, which precedes a week-long holiday, one of the most popular times for people to travel.

In Xiamen, south of China, 32 new cases of community transmission have been reported on September 13 as opposed to just one case a day earlier. The first patient was a close contact of someone diagnosed with COVID-19 in Putian, health authorities said.

Some areas in Xiamen have been totally locked down due to a higher virus risk, and schools have been advised to move to learn online. Public venues such as cinemas, gyms, and bars have been closed and residents told not to leave the city as authorities began testing for the coronavirus.

China has now been hit by multiple outbreaks of the highly contagious Delta variant after quashing the first wave of the coronavirus that emerged from Wuhan in late 2019.