Brihanmumbai Municipal Corporation (BMC) Commissioner Iqbal Singh Chahal said on Wednesday that the second of Covid-19 has begun in Mumbai even as the city reported 91,000 Covid-19 cases were reported in 49 days. He further said 7,4000 people are asymptomatic, while 17,000 are showing symptoms of Covid-19 and 50 per cent have mild symptom.