Chinese authorities ordered mass COVID testing in the city of Wuhan after its first non-imported cases in more than a year.
The coronavirus was first detected in 2019 in the central Chinese city of 11 million people but, over the course of the pandemic, China has been largely successful in containing outbreaks through quick lockdowns and mass testing of the population.
The current outbreaks in China, while still in the hundreds of cases in total, have spread much more widely than previous ones, reaching multiple provinces and cities including the capital, Beijing.
Three cases were confirmed in Wuhan on Monday.
Many cases have been identified as the Delta variant that is driving outbreaks in many countries.
The National Health Commission said on Tuesday that 90 new cases had been confirmed the previous day, 61 locally spread ones and 29 among people who had recently arrived from abroad.
Most of China's local cases are in Jiangsu province in the eastern part of the country. The outbreak started at the airport in the provincial capital.
Authorities reported 45 new cases, five in Nanjing and 40 in the city of Yangzhou, which was conducting a second round of mass testing,
Five other provinces and the cities of Beijing and Shanghai also reported new local cases in the single digits.
Beijing has reported a total of five cases in recent days.
Government-affiliated scientists have said that Chinese vaccines are less effective against the new strains of the coronavirus but still offer some protection.
Only Chinese vaccines are currently being given in China, where authorities say more than 1.6 billion doses have been administered.