the Great Wall stretches over 21,000 kilometers. (File Photo)

China will launch a campaign to crackdown on criminal damage to the country's historic treasure- the Great Wall- which has faced decay in many places.The campaign will be launched by China's State Administration of Cultural Heritage (SACH) which will involve regular inspections and random checks on protection efforts by authorities in 15 provinces, autonomous regions and municipalities.The SACH will open a special tip-line for information about violations and damage to the Great Wall from the public, state-run Xinhua news agency reported.Built from the third century BC to the Ming Dynasty (1368-1644), the Great Wall stretches over 21,000 kilometers from the northwestern province of Gansu to north China's Hebei Province.Over a four million tourists visit the Great Wall every year as it is the centre of China's tourism campaign.Each tourist pays about USD 17 to visit different places, specially in Beijing.According to SACH statistics, about 30 per cent of a 6,200-km section of the wall built in the Ming Dynasty has disappeared, and less than 10 per cent is considered well-preserved.The Great Wall has faced threats from both nature and humans.Earthquakes, rain, wind and other natural elements have left the wall with many decayed and crumbling bricks.Human activities, such as reckless development by some governments and theft of bricks by local villagers for use as building materials, as well as agriculture near the wall, have damaged the landmark, according to a research by the China Great Wall Society.The lack of protection efforts in remote regions and a weak plan have also contributed to the damage, the society said.In 2006, China released a national regulation on Great Wall protection.However, Great Wall experts have urged local authorities to draw up more practical measures to better implement the regulation.This year, Inner Mongolia Autonomous Region included Great Wall protection expenditures in its budget.The government of Fangcheng City, Henan Province, began a campaign for conservation experts and local residents to work together to protect the wall.