Hundreds of protestors in towns across the eastern Indian state of Orissa have been demonstrating against a government order that iodine must be added to salt.

They say that the order, and a government ban on the sale of common salt, are unconstitutional.

They also say the directive will put salt producers out of business and force the poor to pay much more for the product.

The Indian government, on the advice of United Nations health officials, implemented the order as a means of reducing iodine deficiency, which can cause birth defects, mental retardation and goitre.