As we've been reporting, more than a billion people in India have been asked to observe a "total lockdown" for the next 21 days in an attempt to stave off the coronavirus pandemic.

The capital Delhi and several state governments began partial shutdowns on Sunday, when Prime Minister Narendra Modi warned people were not taking measures seriously enough.

Now Mr Modi says no citizen in the country will be allowed to leave their home.

There have been more than 500 confirmed cases across India. At least nine people have died.

Image source, Getty Images

Image source, Getty Images

Image source, Getty Images

Image source, Getty Images

Daniel Sandford
Home Affairs Correspondent

Is the military going to be brought in to reinforce the government’s present plans and help with a lockdown?

The military is already involved in all sorts of things, for example, delivering oxygen and protective equipment to hospitals.

There is no plan at all at the moment for the military to be involved in enforcing the lockdown.

I can see a scenario, a long way down the path if things get really bad, where the army might get involved in guarding things like nuclear power stations to allow armed police to do more regular police work.

But there is no suggestion at any point that the army would enforce any lockdown.

Daniel Sandford
Home Affairs Correspondent

Can we report people in the street for socialising in groups, and who do we contact?

At the moment because it is not against the law - although it will be very soon - it is difficult to deal with.

If you feel people are flouting this guidance from the government then you can ring the police. Note that it is not a 999 issue - you can contact police through the non-emergency number.

Everyone is hoping peer pressure will do a lot of this and there will not have to be a lot of enforcement.

The police and government hope people saying to others "why are you doing this?" might have some enforcement effect.

Daniel Sandford
Home Affairs Correspondent

With regard to the rules about exercise, am I allowed to drive to the park and then walk there?

This is quite a controversial one. I think strictly according to what the government says it is absolutely OK, because if you are going somewhere where there are fewer people then it should be allowed.

But a lot of people are criticising that, saying it is unnecessary travel.

The key thing is the government wants you not to do lots of unnecessary things and ministers understand you will want to take exercise.

If you can take it as far away from other people as possible - and that might be by driving to a park where not many people are - then great. If you drive to the park and everyone else has driven to the park then that’s not OK.

The government wants people to make common-sense decisions.

Pallab Ghosh
Science correspondent, BBC News

There is overwhelmingly strong support from scientists for Boris Johnson's new stringent measures. Some thought they should have been brought in sooner.

I've spoken to a number of epidemiologists not involved in the UK government's response who said at the time they were surprised and disappointed more Draconian measures were not introduced earlier.

There is a view that if these measures had been brought in earlier, we might not be seeing this sharp increase in deaths and cases.

Image source, Getty Images

New measures against the outbreak have been announced in the Republic of Ireland.

Taoiseach Leo Varadkar said theatres, playgrounds, clubs and gyms are to shut, while most outdoor gatherings of more than four people could be broken up by police.

And in a similar step to that taken by the UK on Monday, the Irish prime minister asked people only to leave home:

• For work if it is essential
• For essential supplies such as food
• To care for the vulnerable
• To exercise

The restrictions will stay in place until 19 April.

At least 400,000 cases of coronavirus have now been confirmed worldwide, a new milestone in the number of infections, according to data collated by Johns Hopkins University.

The university has been keeping track of the number of coronavirus cases and deaths on its online global dashboard, external.

Its data shows the number of confirmed cases has grown exponentially in the past few weeks, with European countries in particular reporting a huge surge in infections.

Global cases surpassed 100,000 on 6 March, 200,000 on 18 March, 300,000 on 21 March and 400,000 on 24 March, the university's dashboard shows.

Here are the five countries with the most cases:

• China, with 81,591 cases
• Italy, with 69,176 cases
• The US, with 49,768 cases
• Spain, with 39,676 cases
• Germany, with 31,991 cases

Yolande Knell
BBC Middle East correspondent

Jordan’s government has started delivering basic goods, medicines and fuel to its population of 10 million, after announcing an indefinite curfew to deal with the coronavirus.

On social media, Jordanians have shared videos of buses being mobbed, external in some neighbourhoods while in others, locals have queued in a safe, orderly fashion.

“It’s trial and error at a very critical time," says Amman resident Lubna Wardeh, as she waited for a bus with supplies to arrive on her street so she can buy bread and water.

“Those people who went crazy put our quarantine back at zero,” she said.

A government minister praised "citizen's discipline" for spacing themselves as they queued:

The curfew – one of the strictest in the world - was introduced on Saturday because people were ignoring requests to stay home.

Now, anyone caught outside could be jailed for a year.

Mark Lowen
BBC News, Rome

Italy has now recorded 69,176 cases of coronavirus – that’s an increase of just over 8% on Monday's figures.

Deaths have also risen again - 743 people infected with the virus have died in the past 24 hours, up from 601.

Nationwide restrictions are now likely to tighten further, with Italy's Prime Minister Giuseppe Conte announcing on Tuesday that the fine for breaking the rules is set to increase; from a maximum of €206 (£190) to €3,000 (about £2,750).

Much now depends on the rest of this week: if the infection rate declines, the government will be able to tell Italians that their sacrifice is finally paying off.

Gary O'Donoghue
Washington Correspondent

US President Donald Trump is being a little ambivalent and ambiguous about when he thinks this lockdown will end, perhaps suggesting people could return to work soon, and asking out loud if the cure is worse than the virus itself.

He is giving some quite mixed messages that will be concerning scientists.

Public perception of the US response to the virus depends on where you live: the US is very divided between its coasts and its central regions.

Some places haven't been touched by the virus much at all so far but other places have been hit very hard.

Donald Trump is doubling down on previous comments that the US should immediately reopen the economy, bucking advice of health experts. “You can destroy a country this way by shutting it down,” he said on Tuesday.

“You’re going to lose more people by putting the country in a massive recession” or depression. “I would love to have the country opened up and just rearing to go by Easter.”

Vicki Young
Chief Political Correspondent

Think back to the chief scientific officer last week saying that for every death from coronavirus, they estimated there would be around 1,000 cases. That’s a huge number of people already suffering from the disease.

What we don't know is how many are being hospitalised or need intensive care. They not only need ventilators and equipment, they need the staff.

People will think it is good that the steps announced by Matt Hancock today, such as the creation of a new hospital in the ExCeL Centre, are being taken.

But it is also a sign of what is to come - and particularly the difficulties in the capital, where this virus is spreading very quickly.

Just before we brought you the news from Italy, we were following UK Health Secretary Matt Hancock's briefing.

Here are some of the key points that came out of it:

• A temporary 4,000-bed hospital will be opened at the ExCel conference centre in London. It will be called the NHS Nightingale Hospital

• 250,000 volunteers are being sought to help the NHS. The NHS volunteer responders scheme will help with shopping and delivering medicines
• 11,788 former medics have already responded to the UK's call to return to the NHS, including 2,660 doctors and 6,147 nurses
• From next week, 5,500 final year medics and 18,700 final year student nurses will "move to the frontline" of the NHS
• The government has bought 3.5 million antibody tests to determine whether people have certain types of antibodies - created in the body to fight infection - and have therefore contracted the virus

Italy is currently the worst-affected nation, with 6,820 now reported dead from coronavirus, according to the latest figures.

But the rate of infection has seemingly slowed there in the last few days, raising hopes that strict social-distancing measures are having an effect.

On Tuesday, Italian officials said the number of confirmed coronavirus cases had jumped by 3,612 to 69,176, which is about a 1% decrease in new cases on the previous day.

BBC Rome correspondent Mark Lowen said the continued slowing of new cases in Italy is “starting to look like a trend”, external.

The outbreak is far from under control yet, however.

Earlier, Angelo Borrelli, Italy's civil protection chief, told newspaper La Repubblica it was "credible" to estimate the numbers of infected are 10 times higher in reality.

"In the next few hours… we will see if the growth curve is really flattening," he told the paper.

Italy - the world's worst-affected country with 6,820 confirmed deaths so far - has been under prolonged lockdown in an attempt to limit the spread of infections from the worst-hit northern region of Lombardy.

But why has Italy been so badly hit by this pandemic?

Pierluigi Cocco, an Italian epidemiologist based in the Sardinian capital of Cagliari, tells the BBC that while it is too early to determine the reasons behind this, there may be many.

"One could be genetic," he says, meaning the effects of the virus "may vary across ethnic groups as well as individuals".

"Some can carry the virus without any symptoms, and others die quickly, with a whole range of severity in between," he says.

He adds that Italy has one of the highest numbers of elderly citizens in the world - the elderly are generally more susceptible and more prone to develop serious consequences once infected.

Image source, Getty Images

There are other contributing factors, he says, such as the cultural and social attitude of Italians, who "like to meet in large groups and exchange signs of affection with each other". Families also remain close, with generations often socialising together.

In addition, he adds, a possible reason behind the higher mortality rates in the north is air pollution.

"The levels of industrial activity in that area, coupled with urban traffic and the climatic peculiarities of the Po Valley worsen air pollution, thereby increasing the prevalence of respiratory diseases that make people more susceptible to the effects of Covid-19."

As we just mentioned, today's troubling death toll from Italy comes as the numbers had started to slow down in recent days.

Thursday: 427 (3,405 in total)

Friday: 627 (4,032)

Saturday: 793 (4,825)

Sunday: 651 (5,476)

Monday: 602 (6,078)

It does appear as though the number of new cases is slowing down, however, our Rome correspondent Mark Lowen says.

Italy has just reported a jump of 743 deaths in the past day - 141 more than Monday.

This brings its death toll up to 6,820.

This comes after two days of the number falling. Italy has recorded more deaths than China, where the coronavirus outbreak began.

Matt Hancock reveals the government has bought 3.5 million antibody tests, that will be able to tell people whether they have had the virus.

"Those will come online very soon," he says.

He adds that a new testing facility has opened today in Milton Keynes.

He also says 7.5 million pieces of protective equipment have been ordered for NHS staff.

Asked about pictures of crowded underground trains that have emerged over the past few days, Matt Hancock says there should be more Tube services to get people to work.

He says Tube services should preferably be running "in full" to help get key workers such as NHS staff into work.

London mayor Sadiq Khan had earlier urged people to stop packing into the Tube, saying more people would die if they continued doing so.

There's a question about whether boyfriends and girlfriends are allowed to meet up if they don't live together.

England’s deputy chief medical officer Dr Jenny Harries says as a "principle" people should stay in their "household units".

Doing otherwise would help the spread of the virus, she says.

She suggests couples should "test" the strength of their relationship and decide whether they want to live permanently with each other.