Aas has been acting mayor of the Estonian capital since September 2015, when the Harju County court suspended mayor Edgar Savisaar. Savisaar is facing charges for corruption, embezzlement, misappropriation of public funds, large-scale money laundering, and having accepted illegal political donations.

Center Party chairman and Prime Minister Jüri Ratas said that Aas was doing and would do well as mayor, as he had contributed to the development of the city, was experienced, and had the trust of the voters.

Ratas also stressed that the Center Party had been in power in Tallinn for 16 years and achieved a lot in this time.

The campaign of the Center Party in the upcoming local polls would concentrate on providing activities for the young, working to improve the situation of the elderly, and make healthcare services more accessible.

Aas told ERR in an interview that this time his role in the election would be different, as he would need to be the driving force in the campaign. Aas only got 227 votes to his name in the last local election.

Aas has been a member of the Center Party since 2002.