Regulators want the 18 largest wineries in California's San Joaquin Valley region to reduce pollution from their plants by 35%.

America's first air quality controls on wineries are meant to restrict smog-forming chemicals released into the atmosphere during fermentation in one of the country's most polluted air basins. The Air Pollution Control District recently approved new rules for the valley, home to over 100 wineries including some of the nation's largest, such as E&J Gallo.

Wineries can pay other industries, such as neighbouring dairies, to cut their pollution if changes in the production process are too expensive, and can choose instead to pay into a fund to help other communities reduce pollution.

Valley wineries produce some 338m gallons annually, about 70% of California's table wine.