New Delhi, Apr 21 (IANS): With three areas more added to the list, the number of red zones set up across the national capital to control spread of coronavirus reached 87 on Tuesday.

The three new containment zones are in the East, South and South-East districts.

In the South-East district, Gali number one (Shiv Mandir wali gali) Harsh Vihar, Hari Nagar Extension has been sealed after four cases of coronavirus were found, while in the East district, the area between House number 300 to 739/16, Gali number 3, Krishna Puri, Main Road Mandawali has also been made a containment zone.

In the South district, Gali numbers 2,3 and 4 in Devli Extension were made a containment zone on Tuesday.

Among the districts, the maximum containment zones are in the South-East District with 19 such zones, followed by the West district with 13 red zones.

The containment zones are announced by the district administration after three or more COVID cases are found in an area. There has been a constant increase in the containment zones in the city since April 8, when they only numbered 20.

After the administration seals a 'containment zone', the Delhi government starts 'Operation SHIELD' -- Sealing, Home Quarantine, Isolation and Tracking, Essential Supply, Local Sanitisation and Door-To-Door Checking -- to control the spread of the virus in the area, the Delhi Health Department said.

The containment zones -- created to map the local transmission of the disease and prevent the contagion from spreading -- completely shut down movement of the common people with the authorities taking care of essential supplies and properly sanitising the area and the houses in it.

Delhi has reported more than 2,150 cases and 47 deaths related to Covid-19 so far.