The UK's 'red list' now bars travel from India to contain the spread of COVID-19 variants. Here's what it means, which countries are on the list and how it works.

• India is now on the UK's "red list" to prevent the spread of a new COVID-19 variant identified there.
• Travel from the 40 countries on the list is only permitted for UK residents and citizens, after a mandatory quarantine.
• There are no exemptions to avoid quarantine and no way of being allowed to shorten it.

As India's daily COVID-19 cases surge to global records, the UK has added the country to its "red list" of places from which travel is banned to to prevent the spread of coronavirus and its variants.

The red list could be compared to "Level Four: Do Not Travel" advisory issued by the US State Department, which now covers most countries in the world because of the coronavirus.

But while that is a plea for US citizens not to go abroad, the red list works in the opposite direction - it forbids travel from 40 countries.

India was added at 4 a.m. on Friday, after 77 cases wre confirmed in the UK of the "double mutant" B.1.617 variant - which contains two mutations of the original virus - that was identified in India.

Before this, anyone who had been there within 10 days could travel to the UK if they self-isolated on arrival and tested negative twice.

Now, only UK and Irish citizens and those who permanently reside in the country can enter - and only after a 10-day quarantine in an approved hotel where they are closely monitored.

A quarantine requirement for 33 countries was first introduced on February 15 to stop the spread of coronavirus variants that may be more transmissible or deadly.

The red list has been expanded in the last two months. Kenya and the Philippines were added on April 9, along with India's neighbors Pakistan and Bangladesh.

Prime Minister Boris Johnson did not rule out adding France to the list earlier this month but stressed "it would have consequences" given the scale of trade between the two countries.

All the 40 countries are in Central America, South America, Africa, the Middle East or Asia.

The red list in full: Angola, Argentina, Bangladesh, Bolivia, Botswana, Brazil, Burundi, Cape Verde, Chile, Colombia, Democratic Republic of the Congo, Ecuador, Eswatini, Ethiopia, French Guiana, Guyana, India, Kenya, Lesotho, Malawi, Mozambique, Namibia, Oman, Pakistan, Panama, Paraguay, Peru, Philippines, Qatar, Rwanda, Seychelles, Somalia, South Africa, Suriname, Tanzania, United Arab Emirates (UAE), Uruguay, Venezuela, Zambia, Zimbabwe.

Countries are added by ministers, who review scientific data and advice from experts in infectious disease at the UK's Joint Biosecurity Centre, the Department for Transport told Insider.

Ministers consider a country's capability to monitor and sequence COVID-19 variants, how fast coronavirus is spreading in the community there and the number of cases, and any evidence new variants are coming to the UK from that country.

Those quarantining in hotels must test negative on day two and day eight and cannot leave for any reason. There are no exemptions.

One couple who quarantined in February passed the time by exercising, playing cards and watching 70 episodes of "Suits."

Travellers must pay the bill. A single person pays £1,750 ($2,435) and every extra person in a party cost another £650 ($904). For children aged between five and 12, it is an extra £325 ($452).

Failure to quarantine can mean a fine of £10,000 ($13,913).

More than 500 people - a tiny proportion of those who've travelled to Britain - have been fined for failing to isolate

Lucy Moreton, a spokesperson for the ISU union that represents borders, immigration and customs staff, said there were isolated examples of people refusing to quarantine.

"We are seeing a small number of individuals leaving. They don't want to go, so they don't," she said. "We know in the first 24 hours of starting hotel quarantine in Northern Ireland, three people had left."

Since the start of the pandemic, police have issued 511 fines in England and Wales to people who failed to self-isolate after arriving from a country on the UK government's quarantine list, according to the National Police Chiefs' Council.

The number is 0.0044% of the approximately 11.6 million people who have travelled into the UK since the start of restrictions.

British residents who travel abroad without an essential reason - such as work, education or family - face a £5,000 ($6,957) fine for doing so, until the restriction on international travel is lifted.

The Home Office said it could not provide figures on how many of these fines had been imposed.

A lack of reliable data can result in countries being added to the red list at short notice, long after a COVID-19 outbreak appears to have taken hold.

Professor Linda Bauld, a public health expert at the University of Edinburgh, said Britain's previous policy of "travel corridors" (in which travel to certain countries with low case rates was allowed with fewer restrictions) suggested it was using a threshold of the number of cases to determine which countries to add.

"That's almost meaningless because countries are testing at different levels," she said.

"It's difficult to say there's a strong scientific rationale why some countries are on a list and others aren't, when other countries are likely close to the threshold."

But Bauld said quarantine has proven effective in countries like Australia, New Zealand, Taiwan, and Vietnam that mandated them from an early stage and have kept infections low.

Bauld is producing a paper for the Independent SAGE group, a group of scientists set up to provide an alternative voice to the government's scientific advisory group, that will urge authorities to waive quarantine fees for low-income passengers who were forced to travel for family reasons such as bereavement.

Before the pandemic, 92 direct flights departed from India to the UK every week, carrying up to 22,737 passengers, according to VisitBritain. Hundreds of thousands more travelled weekly through connecting airports to the UK.

In January, just 631,500 passengers arrived at British airports - down 91% from the 7.1 million who flew into the country the previous January, before the pandemic.