Coronavirus in South Asia: Where are numbers going up again?
India has the third largest number of coronavirus cases in the world, and its infection numbers are rising again.
Neighbouring countries are also seeing cases rising, as they attempt to ramp up vaccination programmes which only started in the last couple of months.
What's happening to cases in India?
India's population of 1.3 billion dwarfs that of its neighbours, so it's no surprise that its overall infection numbers are much higher.
It's now reported more than 100,000 cases in a single day, which is higher than the daily peak during last year's initial coronavirus wave.
And the Indian authorities recently reported the presence of a "double mutant" variant, leading to concerns that this might make the virus more transmissible.
Virologist Dr Shahid Jameel says this variant could be one of the reasons for a sudden surge in India.
He explains that such a mutation in key areas of the virus's spike protein "may...allow the virus to escape the immune system".
However, more research is needed to understand exactly what this mutation might mean for the spread of the disease and its impact on those who are infected.
India is now ramping up its vaccination programme, which began in mid-January.
More than 60 million people have had one dose, and over 10 million two doses, with the criteria for those eligible for a jab being expanded.
What's happening elsewhere in the region?
Some of India's neighbours are also experiencing an increase in infections.
After going through a second wave in October, Pakistan is witnessing a third surge with infections picking up sharply throughout March.
It has imposed new restrictions in areas with rising cases, making masks mandatory and limiting public gatherings.
Bangladesh imposed a seven-day nationwide lockdown until 11 April amid another big surge in cases there.
Transport services and retail activities have been suspended, and public bodies and private businesses have been told to limit their hours and operate with minimal staffing.
Both countries began their vaccination programmes in the last two months, starting with frontline health workers.
So the proportion of their populations who are vaccinated is currently very small.
In Nepal, there are fears of a second wave, as the country attempts to restart a vaccination drive delayed due to issues with supplies from India.
Afghanistan has also reported a rise in new cases at the start of April, but there are questions about the reliability of its official figures.
In Sri Lanka, daily cases are - by contrast - coming down after a peak in mid-February.
The country started vaccinating its population in late January, but had to temporarily halt the programme due to supply shortages.
They've since reopened schools and resumed their vaccination drive.
How much testing is done in South Asia?
Testing is the key to finding out how the virus is spreading, but testing rates can vary over time.
The Indian government ramped up testing last year, and on a number of occasions achieved over a million tests a day by deploying increasing numbers of rapid antigen tests.
This fell back after cases subsided in December 2020, but has picked up pace again recently.
Dr Shahid Jameel points out that absolute testing numbers do not really show the scale of the pandemic.
"Testing has to increase based on the test positivity rate, not arbitrarily." said Dr Jameel.
Bangladesh was testing over 18,000 a day during its last peak in June last year, but with the recent surge, nearly 30,000 tests a day are being conducted.
Pakistan has also increased its testing levels.
But the level of testing in these countries has generally been far lower than in other countries.
The World Health Organization (WHO) has a benchmark range for adequate testing of between 10 and 30 per positive case in a country or region.
Anything less than this could mean that the true extent of the virus is not really being picked up.
South Asian countries have ramped up testing and Sri Lanka, India and Pakistan now fall within the range deemed adequate by the WHO.
Sri Lanka ramped up its testing massively to nearly 20,000 a day when it witnessed its peak in February this year. It's come down to around 10,000 now.
But Bangladesh is identifying one positive case for every five tests carried out - well below the WHO benchmark.
It's worth noting that some countries such as Australia report the total number of samples tested while others like South Korea report the number of people tested.
India, Bangladesh, Nepal, Pakistan and Sri Lanka all report the total number of tests performed.