The San Francisco Airport is introducing a ban on plastic water bottles, but there are loopholes

The San Francisco International Airport began Tuesday to ban single-use plastic water bottles, but the restriction has flaws.

The policy still allows sellers to sell water in a plastic container of more than one liter, and the ban does not apply to flavored drinks such as sodas, teas and fruit juices.

Vending machines, restaurants and lounges can sell single-use bottled water if the containers are made of recyclable aluminum, glass or compostable packaging.

"This policy does not apply to drinks served on board an aircraft," reads the instructions.

The airport has about 100 hydration stations in its terminals to allow airlines to fill reusable bottles.

The airport said in 2016 that it was aiming to reach zero waste goal by 2021. It also requires suppliers to use compostable packaging for single-use foods.

"SFO's passenger activity generates about 28 million pounds of waste a year, and SFO is committed to ensuring that this waste does not end up in a landfill," the airport said.

Last year, California became the first state to limit the use of plastic straws in restaurants. The law, which was implemented this year, also has a loophole. Restaurants can provide plastic straw if a customer requests one.

The state also prohibits some stores from giving single-use plastic bags to customers.