Iranians are due to choose a new president this month at a pivotal time for the country, both at home and abroad. Much has changed in the four years since the last election - and here are key reasons why this one will be closely watched. Growing dissatisfaction Since the last presidential election in 2017, a series of events has drastically changed the Iranian political landscape. They include deadly crackdowns on anti-government protests; arrests of political and social activists, executions of political prisoners; the shooting down of a Ukrainian airliner by Iran's Islamic Revolution Guard Corps (IRGC); and a severe economic crisis as a result of US sanctions. The repercussions among ordinary Iranians are having a significant impact on the upcoming election. Perhaps the most substantial blow to Iran's rulers would be low voter turnout, as dissatisfaction among the electorate is at its peak. Although it is widely believed that Iranian elections are by no means free and fair (mainly due to the vetting of candidates by a hardline body known as the Guardian Council), Iran's leaders still need high turnout to prove the legitimacy of the political system. It is this legitimacy that has been seriously challenged by the events of the past four years. However, polls by the government-aligned Iranian Students Polling Agency (Ispa) show a 7% drop in expected turnout to just 36% since the list of candidates was announced on 25 May, while the hashtag "No Way I Vote" is now a trend on Persian social media. In previous elections, low voter turnout has usually given the upper hand to the hardliners and conservatives. All eyes on hardliners Since 1997, presidential elections have been polarised, with contenders belonging to hardline and reformist/centrist factions. But a recent directive from the Guardian Council practically barred most reformist or centrist candidates from standing this year. Out of tens of prominent political figures who registered, only seven were approved by the council. Just two of the seven are reformist/centrist candidates, and both are considered low profile. Iran's judiciary chief, Ebrahim Raisi, who was the runner-up in the 2017 election, is the best-known contender, and according to some state polls he is the favourite candidate among the hardliners. Some observers believe the others who have been allowed to stand are only really supporting candidates to help Mr Raisi's bid.