Singapore will impose significantly stricter measures for a month starting next week, to reduce the spread of COVID-19. These include shutting most workplaces, getting schools to shift to full home-based learning,and tightening restrictions on movement and gatherings. In a live televised address to the nation, Prime Minister Lee Hsien Loong likened the moves to a "circuit breaker" that will help bring down the number of cases. Workplaces in Singapore must close from Tuesday (7 April) except for 10 categories of essential services. What are they?