Beginning March, smokers will no longer be able to light up in main squares in Seoul under a toughened anti-smoking ordinance.

The measure, which comes into effect on March 1, affects three main squares in the downtown area, Seoul Plaza, Cheongye-cheon Plaza and Gwanghwamun Plaza, in a bid to reduce the side effects of second-hand smoke in public places, the Seoul metropolitan government said.

As part of a public awareness campaign, the city government will set up warning signs around the squares this month and allow a three-month notification period, city officials said.

When the grace period ends on June 1, those who violate the no smoking ordinance in the specified areas will be fined 100,000 won ($90), they said.

The city plans to designate a total of 321 public places as non-smoking areas this year, adding 23 municipal parks by September and 295 bus stops by December, the official said.

The City Council passed the new ordinance in October last year.