China reported 75 new Covid-19 cases on the mainland Sunday, up from 55 logged a day earlier, including new locally transmitted cases across eight provinces. The wave is part of an expanding Covid-19 Delta variant outbreak in the country that is becoming increasingly severe, following months of little to no locally transmitted cases. China's current case tally stands at 1,022, with no new deaths reported. The country has reported 93,005 infections since the outbreak began. China administered over 1.6 billion doses of Covid-19 vaccines up to July 30. Read: Global Covid situation worsening as cases near 198 million The current wave of Covid-19 in China started in the eastern city of Nanjing, when nine airport cleaners at the Lukou International Airport tested positive during routine testing on July 20. Viral genome sequencing has found all strains to be the fast-spreading Delta variant of the Covid-19 virus, officials confirmed. Variants are continuing their progression, as the Alpha variant was seen in 180 countries, territories or areas, and 13 new countries, territories or areas reported cases of the Delta variant. While the Alpha variant is still detected more often than its counterpart, the Delta variant is believed by the World Health Organization to be 50% more transmissible and might become the dominant form of the virus in the next few months.