The head constable posted at Alipur police station tested positive for COVID-19 on Friday, they said.
"The 11 policemen who have been quarantined worked with the head constable who has tested positive for coronavirus," a senior police officer said.
It is not clear how the head constable contracted the disease.
So far, around 30 Delhi Police personnel have tested positive for coronavirus.
The Delhi Police has sanctioned Rs 1 lakh each to its personnel who have tested positive for the infection while on duty, officials had said on Friday.
The police headquarters will arrange the payment from the Delhi Police Welfare Society for the personnel expeditiously through the concerned DCPs.
On Thursday, Lt Governor Anil Baijal had directed authorities to create a dedicated COVID-19 facility to treat the infected Delhi Police personnel. NIT DIVDIV