According to the Pakistani government, about 12,000 rock carvings, known as "petroglyphs," are to be found along the Indus River.

Many depict Buddhist statues and towers, and are said to have been carved by pilgrims, traders and others in the far distant past to as late as the 10th century.

However, slogans such as "National campaign to eradicate polio," often painted on and around the carvings, have highlighted that current measures taken to protect the historic artworks are proving insufficient.

At present, the graffiti is removed using chemicals, but fears that this may also damage the carvings mean that this is an extremely delicate operation.