Although China has invested 250 million yuan per year since 2005 in excavating and protecting the ancient capital, the ruins close to urban areas are still damaged.

Liu Qingzhu said that in recent years, many new construction projects have begun within the vicinity of the ruins. These buildings are illegal and do not have approval from the national cultural relics administrative department. Some high-rise buildings have caused damage to the ruins

Liu said, "We have explored less than 0.1 percent of the whole area of the Han Dynasty palace. Although after 50 years of excavation we've been able to map out the basic layout of the city, it will take another few hundred years and the efforts of several generations to fully explore such a large site."