April 28, 2020

Amid the Covid-19 pandemic, the Central Public Works Department (CPWD) issued the advisory to its officials to address concerns associated with the spread of the disease via air conditioners and ventilation systems.


  • The guidelines state “Set air conditioners room temperature between 24 degrees Celsius and 30 degrees Celsius and maintain relative humidity between 40 per cent and 70 per cent.

  • The guidelines were formulated by the Indian Society of Heating Refrigerating and Air Conditioner Engineers (ISHRAE) .

  • It quotes a study that found the transmission of Covid-19 in 100 cities in China lower in high temperature and high humidity. It also quotes a study which has shown that the SARS-CoV-2 can live for 14 days on a surface at 4 degrees Celsius, one day at 37 degrees Celsius and will die in 30 minutes at 56 degrees Celsius.

  • Humidity can affect the infectivity — the ease with which infections can take place — of the virus through respiration. In a dry environment, or when there is low humidity, it is easier for foreign particles to invade the body.