Restaurants, bars, gyms and swimming pools will remain shut, the state government said, adding home deliveries and other online services will be permitted.
All social, cultural, entertainment and academic gatherings have been banned.
Pharmacies, shops selling medical equipment and grocery shops are exempted from the partial lockdown.
Counting for the eight-phased Assembly elections will take place on May 2. The state government has said all anti-Covid rules will have to be followed at the counting centres.
The daily surge of coronavirus reached a new high in Bengal on Thursday, with the state logging highest-ever 17,403 fresh cases.
The number of fatalities was also the highest, with 89 deaths recorded in a day. The positivity rate has climbed from 6.79 per cent ten days ago to 7.81 per cent.