Around 2,500 locals turned up at Muang Chiang Mai public park, where a heavily pregnant Paetongtarn appeared via video call on a giant screen to campaign ahead of the May 14 election.
The youngest daughter of fugitive former PM Thaksin Shinawatra is eight months pregnant and due to give birth to her second child next month.
She wished people in Chiang Mai and other northern provinces a happy and safe Songkran festival.
She also expressed concern over the severe PM2.5 air pollution afflicting the city and its effect on tourism over the Thai New Year.
Levels of PM2.5 soared to 148 milligrams per cubic metre (μg/m3) on Thursday, according to the Pollution Control Department.
Thailand’s safe limit for PM2.5 – fine-dust pollution linked with early death from heart and/or lung conditions – is 50μg/m3.
Chiang Mai was second only to Beijing in the rankings of the world’s most polluted cities published by air quality-monitoring website IQAir on Thursday.
"If Pheu Thai is elected, we will accelerate efforts to pass the clean air law to combat PM2.5 as soon as possible," Paetongtarn said.
She urged Chiang Mai locals make this a reality by voting for Pheu Thai.
Chiang Mai is a Pheu Thai stronghold and the hometown of fugitive former PM Thaksin, the party’s patriarch and Paetongtarn’s father.
Pheu Thai party-list MP candidate Danuporn Punnakan told supporters at the Chiang Mai rally that the party's pledge to hand out 10,000 baht via digital wallets to all Thais aged 16 and above would stimulate the grassroots economy.
He said Pheu Thai would turn Chiang Mai province into a new economic zone and a hub for digital nomads by easing visa restrictions.
"This policy aims to generate income, create jobs and boost potential of Chiang Mai locals," he said.
Pheu Thai senior member and party-list candidate Chaturon Chaisang said the party's pledges could become reality but the party was being obstructed by dictatorship.
He said Pheu Thai once held all MP seats in Chiang Mai. It was unable to form the government in 2019 despite winning the highest number of seats in the House of Representatives, he added.
"Chiang Mai people have suffered from dictatorship for many years,” he said. He claimed that many businesses had been forced to close as a result.
He blamed the current government for failing to take care of farmers, resulting in crop burning that has worsened Chiang Mai’s air pollution.
"However, Pheu Thai has solutions for air pollution, such as promoting carbon credit trading and allowing people to take care of their forests," he said.
Echoing Paetongtarn, he asked Chiang Mai people to vote for Pheu Thai in order to put an end to “dictatorship”.
After the campaign event, Chaturon and other Pheu Thai members boarded a truck to participate in Songkran water splashing with Chiang Mai locals.
Traditional Songkran celebrations have resumed in the northern city after three years of Covid-19 restrictions.