Over a quarter of the global population is currently in lockdown as countries across the world bring in severe restrictions as part of efforts to contain the spread of the coronavirus pandemic. India, which alone accounts for almost a fifth of the planet's humans, became on Wednesday the latest country to enforce a nationwide lockdown, with South Africa due to also take up the measures on Thursday. Under lockdown, schools and all non-essential businesses are closed, and people are obliged to stay at home, but are allowed to go out to buy necessary food or medicine, or seek medical help. Among the most extreme measure are those in Jordan, where residents were not allowed to leave their homes under any circumstances for three days, and the restrictions were brought in with the ringing of air raid sirens, a move usually reserved for war time. Some countries have opted for partial lockdown, such as China, where Hubei province – the origin of the pandemic – remains closed off, while the rest of the country is under less strict measures. In the US, some states have gone for full containment, including California, Illinois and New Jersey, with New York the most affected city. Other countries, such as Saudi Arabia, have imposed less strict measures, requesting the population stay at home voluntarily, with some enforcing evening curfews.