The nation is battling the coronavirus outbreak with a grass-roots mobilization reminiscent of Mao-style mass crusades not seen in China in decades, essentially entrusting front line epidemic prevention to a supercharged version of a neighborhood watch.

Housing complexes in some cities have issued the equivalents of paper hall passes to regulate how often residents leave their homes. Apartment buildings have turned away their own tenants if they have come from out of town. Train stations block people from entering cities if they cannot prove they live or work there. In the countryside, villages have been gated off with vehicles, tents and other improvised barriers…

Residential lockdowns of varying strictness — from checkpoints at building entrances to hard limits on going outdoors — now cover at least 760 million people in China, or more than half the country’s population, according to a New York Times analysis of government announcements in provinces and major cities. Many of these people live far from the city of Wuhan, where the virus was first reported and which the government sealed off last month.