Polls have opened in Mexico, where thousands of posts at the local, state and national levels are up for grabs in what has been described as the biggest vote in the country’s history. Sunday’s midterm elections will determine the makeup of the 500-seat Chamber of Deputies, the lower house of Congress, as well as 15 governorships and thousands of mayoral and local councillor positions. Mexico’s National Electoral Institute (INE) said more than 20,000 positions are being contested, while nearly 95 million people are eligible to vote. The lead-up to Sunday’s elections was marked by wides...