ANKARA - Turkey holds municipal elections across 81 provinces on Sunday March 31, with President Tayyip Erdogan's AK Party (AKP) aiming to reclaim cities it lost in 2019, including the country's largest city of Istanbul and the capital Ankara.

On Sunday, polling stations will be open from 7 a.m. to 4 p.m. in eastern provinces and from 8 a.m. to 5 p.m. in the rest of the country. Initial results are expected by 10 p.m. (1900 GMT) on Sunday.

Analysts see the vote as a nationwide gauge of Erdogan's support and the opposition's durability, especially that of Mayor Ekrem Imamoglu of Istanbul. A tight race is expected in the city that is home to more than 16 million people and drives more than a quarter of the nation's GDP.

WHAT'S AT STAKE?

In the last local vote in 2019, the main opposition Republican People's Party (CHP) shocked Erdogan when it prevailed in Istanbul and Ankara and ended more than two decades of rule by the AKP and its Islamist predecessors.

Erdogan, who has ruled Turkey for more than two decades and campaigned hard for the AKP in recent weeks, launched his political career as mayor of Istanbul in 1994.

Almost 11 million people are eligible to vote in the city, the Supreme Election Council says. Turnout in both general and local elections is very high in Turkey at close to 90%.

Incumbent CHP Mayor Imamoglu's main challenger is the AKP's Murat Kurum, a former government minister. Polls give Imamoglu a slight edge.

Last May, Erdogan was re-elected president and his alliance won a majority in parliament in tight general elections - a result that splintered and disheartened an alliance of the CHP and other opposition parties.

WHY DOES IT MATTER?

The budget of Istanbul metropolitan municipality dwarfs all other 80 cities in the country at 516 billion lira ($16.05 billion) in 2024, including its subsidiaries. The budget of the second city, Ankara, is 92 billion.

Controlling big cities and their budgets can give parties say over financing, contracts and job creation, boosting their popularity on the national stage.

Istanbul holds special importance for Erdogan as he rose to the national political stage during his time as mayor between 1994 and 1998.

Imamoglu has emerged as the opposition's main alternative to Erdogan. If he wins a second mayoral term, he would very likely run in the next presidential vote, analysts say, while a loss could stunt his career and leave the opposition in further disarray.

For Erdogan, regaining Istanbul and Ankara would bolster his pursuit of a new constitution that could potentially extend his rule beyond 2028, which marks the end of his current term, analysts say.

Under the existing constitution, the presidency is limited to two terms. Erdogan secured a third term last year thanks to a legal loophole resulting from the transition to a presidential system in 2018, as his initial term was served under the previous system.

"The electoral test is also significant for Erdogan's pursuit of a new constitution (or constitutional amendments) to side-step presidential term limits and remove the remaining elements of judicial independence," said Wolfango Piccoli, co-President of Teneo.

WHO ARE THE CANDIDATES?

MURAT KURUM, AKP, ISTANBUL:

Kurum, 47, was environment and urbanization minister from July 2018 until last June, leaving the post after the general elections in 2023. He was then elected as a member of parliament for Istanbul.

Born in Ankara, Kurum served at the state mass housing agency TOKI from 2005 to 2009 and later as the general manager of Emlak Konut, a government-run real estate investment trust.

EKREM IMAMOGLU, CHP, ISTANBUL:

Imamoglu, 52, originally from the Black Sea city of Trabzon, was a district mayor in the city before becoming Istanbul mayor.

He won the 2019 election in Istanbul with the backing of an alliance of the CHP, the nationalist IYI Party, and the pro-Kurdish People's Democratic Party (DEM), which is now called DEM. This year IYI and DEM are running their own candidates. Many of Turkey's Kurds are set to put aside party loyalty and back Imamoglu on Sunday, according to pollsters.

CHP'S MANSUR YAVAS, AKP'S TURGUT ALTINOK:

Pollsters say Ankara's incumbent Mayor Mansur Yavas, a former district mayor in Ankara, is comfortably ahead of AKP challenger Turgut Altinok, another former district mayor.

OTHER PROVINCES:

Turks will also vote in the other 79 provinces of the country, casting four votes in total: one for the mayor of their province, one for their district mayor, one for the district council and another for the local administrator of their neighbourhood.

Other competitive cities include CHP-run Antalya, Bursa, and Adana.

($1 = 32.1467 liras)

(Additional reporting by Huseyin Hayatsever, Editing by Jonathan Spicer, Alexandra Hudson)