New Delhi, Sept 01 (ANI): The third phase of sero-survey began in Delhi on Sept 01. Delhi Health Minister Satyendar Jain said, “The third phase of sero-survey is beginning today. This time, it is being done on a ward-wise basis. The sample size is 17,000. The sampling will be completed within a week and it will take 7-10 days after that to process it.” Satyendar Jain also paid condolences over demise of former president Pranab Mukherjee.