As the novel coronavirus spreads from China around the globe, India appears especially at risk because of its dense population, patchy health-care system and high rate of migration.The nation has confirmed just three cases, while the Indian government says 23,531 people are under observation. Neighbouring Sri Lanka has reported one infection, while Pakistan disclosed its first patients this week: Two travelers who had separately returned from Iran, one of whom had been on a tour with 28 people.While India’s numbers look tiny set against a population of 1.3 billion, the World Health Organization has warned that new cases are appearing faster outside China than those within the country where the virus originated. The discovery in the U.S. of a case with no ties to a known outbreak has raised concern that a similar emergence in a country as densely populated as India could quickly overwhelm the chronically underfunded health-care system.“It’s already here, they’ve detected a few cases, and if it starts spreading you will see a very fast” evolution, said Kasisomayajula Viswanath, a professor at Harvard’s T.H. Chan School of Public Health. “Right now they are able to control it, and monitor it, and treat it effectively. But if it is spreading along with other contagious diseases that are already here, then it becomes a matter of considerable concern.”Apart from its sheer size, India is cause for particular worry because of the density of its population: 420 people live on each square kilometer (about 0.4 of a square mile), compared with 148 per square kilometer in China. Places like Mumbai’s Dharavi slum, or even a typical Indian household containing extended families, can facilitate contact with virus-bearing droplets emitted by breathing, talking, coughing or sneezing.Pakistan and Bangladesh look even more exposed than their larger South Asian neighbor. The two spend less on health care than India, and each has an array of entry points from countries where outbreaks are increasing.Pakistan’s first case appears to have come from neighbouring Iran, which has emerged as the center of the outbreak in the Middle East, with at least 245 confirmed cases and 26 deaths. Pakistan has suspended all flights to China, Japan, and now Iran. Like Bangladesh, Pakistan has declined to evacuate students stranded in China. Bangladesh did extract 312 citizens from Wuhan, the origin of the virus, keeping them in quarantine in camps outside Dhaka for 14 days.Like China, India has a high rate of internal migration. In the 2011 census, 450 million people moved from one area to another in search of opportunity. Many commute daily from their villages to work in the cities. That could make it harder to contain an outbreak to one locality, as China has attempted to do by locking down the entire state of Hubei.“That’s not really possible in India,” said Vivekanand Jha, the executive director of the George Institute for Global Health, India, in New Delhi. “Indians, if they are infected, are much more likely to remain in circulation and potentially come in contact with uninfected individuals wherever in the world they might be.”A large-scale outbreak stands to put a heavy strain on India’s economy, which is much smaller than China’s and where growth this year is on track to be the weakest in more than a decade.The country’s health-care spending is among the lowest in the world — just 3.7% of gross domestic product. That’s left India with a patchwork of overcrowded public hospitals, and private ones that are unaffordable for many people.Indian Health Minister Harsh Vardhan said he’s “extremely proud” of his country’s response so far to containing the virus, which includes input from the armed forces, national carrier Air India and embassies abroad. Authorities have been screening travelers at airports, seaports and border crossings. It says the three confirmed cases, all discovered in the southern state of Kerala, have all been discharged from hospital.Still, Padmanesan Narasimhan, a professor of public health at the University of New South Wales who has worked on tuberculosis control in India, said the chances of the disease spreading in India are high.“Because of internal migration, and the population density, and the limited access to health infrastructure, that would be a major challenge in India,” he said.One area where India and its South Asian neighbors may have an advantage over the places where the coronavirus is already spreading is the weather. Coronaviruses of all kinds tend to travel better in cooler, drier climates — it’s why flu season is in winter — and with the subcontinent’s summer approaching, the stifling heat may end up snuffing out the virus, too.Moreover, while health-care systems across the region are underfunded, they do have expertise in fighting infectious diseases, given the prevalence of malaria, dengue and tuberculosis. Wealthier economies, from Hong Kong to Italy to Japan, have struggled to quell the spread of the virus.“If it comes here, certainly it is a matter for concern because of the density of the population, and the sheer scale of it,” said Harvard’s Viswanath. “On the other hand, it looks like we’ve not been able to do a good job globally. I don’t have tremendous confidence in other systems, either.”— With assistance from Faseeh Mangi, Kamran Haider, Bibhudatta Pradhan, Asantha Sirimanne and Arun Devnath.