when 10,000 evacuees from ceded territories to the Soviet Union were settled in the city, and then later in the 1960s and 1970s as a result of urbanization. The rapid population growth came to a sharp end in 1975 and the city has since grown significantly slower albeit more steadily, with the latest notable growth in population happening in 2016 when the municipality of Nastola became a part of Lahti.

In December 2018, Lahti