Spraying disinfectant on the streets, as practised in some countries, does not eliminate the new coronavirus and even poses a health risk, the World Health Organisation (WHO) warned on Saturday.

In a document on cleaning and disinfecting surfaces as part of the response to the virus, the WHO said spraying can be ineffective.

The WHO said: “Spraying or fumigation of outdoor spaces, such as streets or marketplaces, is not recommended to kill the Covid-19 virus or other pathogens because disinfectant is inactivated by dirt and debris.

“Even in the absence of organic matter, chemical spraying is unlikely to adequately cover all surfaces for the duration of the required contact time needed to inactivate pathogens.”

The WHO said streets and pavements are not considered as “reservoirs of infection” of Covid-19, adding that spraying disinfectants, even outside, can be “dangerous for human health”.

The document also stresses that spraying individuals with disinfectants are “not recommended under any circumstances. This could be physically and psychologically harmful and would not reduce an infected person’s ability to spread the virus through droplets or contact”, said the document.

Spraying chlorine or other toxic chemicals on people can cause eye and skin irritation, bronchospasm and gastrointestinal effects, it adds.

The WHO is also warning against the systematic spraying and fumigating with disinfectants on to surfaces in indoor spaces, citing a study that has shown it to be ineffective outside direct spraying areas.

“If disinfectants are to be applied, this should be done with a cloth or wipe that has been soaked in disinfectant,” it says.