The normalized nucleic acid testing in Chengdu will no longer serve the public free of charge, which is mainly related to the following factors:

The local financial department may not be able to bear too much economic burden. As the 1 th place in the ranking of new first-tier cities, Chengdu's population has exceeded 11 million. Under this condition, a normalized nucleic acid test is a big expense for the local financial department. If the normalized nucleic acid test is to be carried out for 3 to 5 times, the financial department will have a great economic burden and no more funds will be invested in other convenient infrastructure. It will cause a lot of obstacles and influences on the overall development of local environment and infrastructure in Chengdu. Based on this consideration, the relevant departments in Chengdu announced that nucleic acid testing will no longer provide normal nucleic acid testing for free in the future, and people need to pay personal expenses.

It may also be related to the empirical factors of epidemic prevention and control in China. From being at a loss in epidemic control to controlling the epidemic in a short time, China has accumulated abundant experience in epidemic prevention and control. Therefore, after an epidemic occurs in many areas, all potential risks can be screened out only by conducting nucleic acid testing once or three times. Based on this reason, the cost of normalized nucleic acid testing once or twice is affordable for people, on the one hand, it will not delay people's economic income, on the other hand, the financial department will not have too much.

it may also be related to the long-term non-ending factors of the epidemic. If the epidemic can end in the next 1~2 years, Chengdu may not announce the normalization of nucleic acid detection and adopt the method of charging. The relevant departments have also announced that they should make long-term preparations to fight the epidemic, so the normalized nucleic acid testing, after long-term free, is unbearable for the local economy, so they have launched a charging project.