Mexico prepares to elect its first female president with one candidate pledging to crack down on cartels and rival vowing to pursue populist politics

Mexican voters are all set to decide on their next president on Sunday - primarily between a former academic and an ex-senator who is also a tech entrepreneur. 

About 100 million people are registered to vote in an election that will likely give the country its first woman president and will replace President Andrés Manuel López Obrador. 

The elections are widely seen as a referendum on López Obrador, a populist who has expanded social programs but largely failed to reduce cartel violence in Mexico.

Frontrunner and Mexico City Mayor Claudia Sheinbaum is running with the Morena party.

Sheinbaum has promised to continue all of López Obrador´s populist policies, including a universal pension for the elderly and a program that pays youths to apprentice.   

Xóchitl Gálvez, the opposition presidential candidate, whose father was Indigenous Otomi, rose from selling snacks on the street in her poor hometown to start her own tech firms. 

A candidate running with a coalition of major opposition parties, she left the Senate last year to focus her ire on López Obrado's decision to avoid confronting the drug cartels through his 'hugs not bullets' policy. 

She has pledged to go after criminals more aggressively. 

A third candidate from a smaller party, Jorge Álvarez Máynez, trails far behind.

The persistent cartel violence, which has seen scores of local candidates killed in a spate of political violence, along with Mexico's middling economic performance, are the main issues on voters' minds.

In this past election season, 145 people with connections to the various races across the country have been murdered. 

About 675,000 Mexicans living abroad are registered to vote, but in the past, only a small percentage have done so. 

However, overall voting turnout has hovered around 60 percent in recent elections. 

Beyond the fight for control of Congress, the race for Mexico City - whose top post is now considered equivalent to a governorship - is also crucial this election. 

Sheinbaum is just the latest of many Mexico City mayors, including López Obrador, who went on to run for president. 

Several gubernatorial races in large, populous states such as Veracruz and Jalisco are also drawing interest.

In addition to the presidential election, a total of 20,000 congressional and local positions are on residents' ballots, NBC News reported.  This includes 500 members of congress and 128 senators.

Polls open at 8 am and close at 6 pm for most of the country today. 

The first preliminary, partial results are expected by 9 pm, after the last polls in different time zones close.