BEIJING, June 13 (Xinhua) -- China has strengthened the scientific, systematic and holistic protection of its world natural heritage, with notable improvements in conservation conditions, the National Forestry and Grassland Administration said Saturday, which marks this year's Cultural and Natural Heritage Day.

According to assessments by the International Union for Conservation of Nature, 90 percent of China's heritage sites received excellent or good overall ratings, significantly above the global average of 61 percent and the Asian average of 68 percent.

China is now home to 15 world natural heritage sites and four heritage sites noted for both cultural and natural features, leading the world in terms of quantity. The sites cover a total area of more than 80,000 square kilometers across 20 provincial-level regions, which take in diverse ecosystems, including mountains, forests, wetlands, deserts and coastlines.

In recent years, China has intensified conservation efforts through a protected area system centered on national parks. More than 80 percent of the heritage sites have undergone nature-based restoration, effectively preserving the authenticity and integrity of their ecosystems, according to the administration.

At the same time, the country has expanded channels to benefit its people and develop green industries such as ecotourism, nature-based study tours and under-forest economy.

World natural heritage sites will be incorporated into the monitoring framework of protected areas and benefit from coordinated protection and development efforts alongside these areas.

The administration will also establish and improve management systems and mechanisms for natural heritage protection, aiming for standardized and high-level management.