Will work with like-minded parties to defeat communal forces: Sonia

New Delhi, Feb 9: As the outbreak of novel coronavirus has lead to the death of more than 800 Chinese nationals, aviation regulator DGCA on Saturday said that foreigners who went to China on or after January 15 will not be allowed to enter India.

The DGCA, in its circular to airlines on Saturday, reiterated that all visas issued to Chinese nationals before February 5 have been suspended.

However, the Directorate General of Civil Aviation (DGCA) clarified, "These visa restrictions will not apply to aircrew, who may be Chinese nationals or other foreign nationalities coming from China."

"Foreigners who have been to China on or after January 15, 2020, are not allowed to enter India from any air, land or seaport, including Indo-Nepal, Indo-Bhutan, Indo-Bangladesh or Indo-Myanmar land borders," the DGCA said.

Among Indian airlines, IndiGo and Air India have suspended all of their flights between the two countries. SpiceJet continues to fly on Delhi-Hong Kong route.

On February 1 and 2, Air India conducted two special flights to Chinese city of Wuhan, epicentre of the outbreak, evacuating 647 Indians and seven Maldivians.

Till date, three Indians have tested positive for novel coronavirus.

London, May 20: The current physical distancing guidelines of 6 feet may be insufficient to prevent COVID-19 transmission, according to a study which says a mild cough in low wind speeds can propel saliva droplets by as much as 18 feet.

Researchers, including those from the University of Nicosia in Cyprus, said a good baseline for studying the airborne transmission of viruses, like the one behind the COVID-19 pandemic, is a deeper understanding of how particles travel through the air when people cough.

In the study, published in the journal Physics of Fluids, they said even with a slight breeze of about four kilometres per hour (kph), saliva travels 18 feet in 5 seconds.

"The droplet cloud will affect both adults and children of different heights," said study co-author Dimitris Drikakis from the University of Nicosia.

According to the scientists, shorter adults and children could be at higher risk if they are located within the trajectory of the saliva droplets.

They said saliva is a complex fluid, which travels suspended in a bulk of surrounding air released by a cough, adding that many factors affect how saliva droplets travel in the air.

These factors, the study noted, include the size and number of droplets, how they interact with one another and the surrounding air as they disperse and evaporate, how heat and mass are transferred, and the humidity and temperature of the surrounding air.

In the study, the scientists created a computer simulation to examine the state of every saliva droplet moving through the air in front of a coughing person.

The model considered the effects of humidity, dispersion force, interactions of molecules of saliva and air, and how the droplets change from liquid to vapour and evaporate, along with a grid representing the space in front of a coughing person.

Each grid, the scientists said, holds information about variables like pressure, fluid velocity, temperature, droplet mass, and droplet position.

The study analysed the fates of nearly 1,008 simulated saliva droplets, and solved as many as 3.7 million equations.

"The purpose of the mathematical modelling and simulation is to take into account all the real coupling or interaction mechanisms that may take place between the main bulk fluid flow and the saliva droplets, and between the saliva droplets themselves," explained Talib Dbouk, another co-author of the study.

However, the researchers added that further studies are needed to determine the effect of ground surface temperature on the behaviour of saliva in air.

They also believe that indoor environments, especially ones with air conditioning, may significantly affect the particle movement through air.

This work is important since it concerns safety distance guidelines, and advances the understanding of the transmission of airborne diseases, Drikakis said.