Authorities had been reluctant to impose a mask requirement in Switzerland's most populous canton, however their hand was forced by rising infection rates.
Events and entertainment venues will no longer be able to have more than 100 attendees, unless there is a compulsory mask requirement.
The decision to implement the mask requirement was made on Monday evening, August 24th.
Zurich now has 65 new infections per 100,000 residents over the past 14 days, above the Swiss government's threshold of 60 per 100,000 which sees countries designated as 'high risk' and warranting quarantine.
Zurich is the second German-speaking canton – and the sixth in Switzerland – to make masks compulsory in shops and supermarkets.
From Monday, August 24th, masks will be required in shops, restaurants and some schools in Basel City.
Basel City became the first German-speaking canton – and the fifth after Geneva, Vaud, Neuchâtel and Jura – to put in place the mask requirement in shops.
Masks have been required on public transport in all Swiss cantons since July 6th.
'We have to act'
On Sunday, Zurich mayor Corine Mauch called for a compulsory mask requirement to be introduced in Switzerland's most populous canton.
Mauch said “we have to act before we lose control”.
“We would like to take further measures”.
Mauch warned that the canton was facing a crucial moment and that a mask requirement should be put in place before authorities “lose control” of the virus. “We must remain vigilant and careful. In this respect, the mask also has a symbolic meaning. It makes the presence of the virus visible,” she said.
Correction: This article previously stated that masks were required in restaurants and bars. As of August 27th, masks are only compulsory in shopping centres, supermarkets, markets and shops in Zurich.