people can only leave their homes to buy food, medicine and to exercise.
They’re allowed to travel, but only to and from work if they cannot do their jobs from home.
Staying at home to keep people safe can be a difficult concept to grasp, especially when you are feeling fit and healthy yourself.
BBC health reporter Laura Foster looks at the statistics which show just how much of a difference it can make when it comes to taking pressure off health services and saving lives.
Stock markets across the Asia-Pacific region fell sharply on Monday, while Wall Street is seen opening sharply lower.
Crude oil prices have also slumped as economies around the world come to a virtual standstill.
Investors are concerned that governments and central banks are struggling to ease the impact of an impending deep global recession.
In early trading in Asia, the Hang Seng index in Hong Kong fell by 5.5%, while China’s Shanghai Composite lost 3%.
New Zealand’s main share index started the day down by more than 10%, and the ASX 200 in Sydney lost 7.2%.
In India, where a 14-hour curfew was announced, its Sensex index fell 10%, triggering a “circuit breaker” and a 45-minute trading halt.