By John Sudworth BBC News, Delhi

Protesters say Coca-Cola may be unsafe

Coca-Cola and Pepsi are challenging the state government of Kerala's claim that the drinks contain harmful pesticides.

The ban on the production and sale of the drinks in the southern Indian state effectively closed a market of 30m potential customers overnight.

The government acted last month following a report by a campaign group.

Results 'flawed'

The Centre for Science and Environment claimed that the Coke and Pepsi contain harmful levels of pesticides.

A number of other Indian states banned the drinks in schools and colleges, but with its outright ban, Kerala went the furthest.

Now the two multinationals have taken Kerala to court.

They argue that only the central government in India has the power to ban food products, and they point out, that it has not seen fit to do so.

Coca-cola and Pepsi also dispute the evidence upon which the ban was based, arguing that the results were flawed.

They say they can verify that the ingredients used to make the fizzy drinks conform to the highest purity standards.