The daily bombardment of emergency hotlines by spam phone calls has prompted telecom management and law enforcement authorities to act in the hope of eradicating the long-standing nuisance.

In April and May, for example, more than 1,600 telemarketing calls were made to the emergency medical service center in Ningbo, Zhejiang province, via the 120 hotline, which is supposed to be reserved for emergencies.

According to official data, more than 90 calls promoting real estate sales come to the center between 9 am and 5 pm on some days, leading managers to report the problem to the police.

On July 12, the prosecuting authority in Haishu district urged Ningbo communications officials to take measures to prevent the nuisance calls.

Ningbo's housing and urban-rural development office also summoned representatives from the real estate companies involved and demanded that they immediately stop the spam. As punishment, the office suspended the issuance of permits that allow property developers to sell apartments before construction is complete.

"With the joint efforts of multiple authorities, the number of spam calls has been reduced significantly," said Li Zhong, the top prosecutor in Haishu. "This further demonstrates that slack attention from authorities has contributed greatly to the growing problem."

A wide range of unsolicited phone calls, including pranks and telemarketing, may be classified as nuisance calls.

On July 30, 13 ministries and other central departments, including the Ministry of Public Security and the Supreme People's Court, issued an action plan to address the matter. A national campaign to combat nuisance calls will run until December 2019.

The Zhejiang Communications Administration said in a statement that it will strictly follow the requirements of the plan and cooperate with other departments to curb the spread of spam calls through a combination of legal, administrative and technological means.

Xu Ting contributed to this story.