Safer to be 'a cow than a Muslim': Shashi Tharoor

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.

New Delhi, Jun 27: Delhi Environment Minister Gopal Rai on Saturday called an emergency meeting here to discuss the situation following a locust attack in neighbouring Gurugram.

The minister also directed the administration to be alert, an official said.

"After the emergency meeting, an advisory will be issued on steps to be taken to deal with the situation," Rai told PTI.

He asked the officials of the Agriculture department to make field visits to areas close to Gurugram.

The development secretary, divisional commissioner, director, Agriculture department, and the district magistrates of South Delhi and West Delhi will attend the meeting, the official said.

Earlier in the day, the skies over many parts of Gurugram turned dark as swarms of locusts descended on the town.

However, the migratory pests are likely to spare the national capital for now, officials said.

The swarms of locusts, spread across two kilometres, moved from west to east. They entered Gurugram around 11.30 am, K L Gurjar of the Locust Warning Organisation, Ministry of Agriculture, told PTI.

The pests, he said, were headed towards Faridabad and Palwal in Haryana.

Alarmed at the invasion of the locusts, which settled on trees, rooftops and plants, many residents of Gurugram shared videos from their high-rise perches.

In May, India battled a devastating desert locust outbreak. The crop-destroying swarms first attacked Rajasthan and then spread to Punjab, Gujarat, Maharashtra and Madhya Pradesh.

According to experts, broadly four species of locusts are found in India – desert locust, migratory locust, Bombay locust and tree locust. The desert locust is considered the most destructive.

It multiplies very rapidly and is capable of covering 150 kilometers in a day.

This insect, a type of a grasshopper, can eat more than its body weight. A one square kilometer of locust swarm containing around 40 million locusts can in a day eat as much food as 35,000 people.

Experts blame the growing menace of desert locusts on climate change. They say breeding of locusts is directly related to soil moisture and food availability.

Mar 7: Two Malayalam news channels, Asianet News and Media One, which were banned by the information and broadcasting ministry for their coverage of the recent violence in Delhi on Friday evening, were allowed to resume telecasting on Saturday morning.

While Asianet News appeared to have begun operations around 7am on Saturday, Media One was screening content by 9.30am.

The ministry of information and broadcasting had imposed a 48-hour ban on Asianet News and Media One for their coverage of the Delhi violence for 48 hours from 7.30pm on Friday. Both Asianet News and Media One were barred under Rule 6(1 c) and Rule 6(1e) of the Cable Television Networks Act, 1994.

The ministry of information and broadcasting alleged Asianet News and Media One were "biased" and critical of the RSS and Delhi Police.

The ban on Asianet News and Media One triggered a torrent of criticism of the move. Congress MP Shashi Tharoor asked how "Malayalam channels inflame communal passions in Delhi?" and alleged some English news channels were continuing "their brazen distortions" with impunity.

In a statement issued on Friday after the ban, Media One termed the move "unfortunate and condemnable" and called it a "blatant attack against free and fair reporting". Media One called it "an order to stop free and fair journalism".