There are many difficult achievements in "Freeze Age 2", and strict law and discipline is one of them. To achieve this achievement, you only need to be in a city with a population of at least 30,000, with no crime and tension, and no population problems. Big, mostly crime and tense, you need a lot of watchtowers and battle centers.
How to achieve the Strict Law and Discipline achievement in Icepunk Age 2
Strict laws and disciplines
Have no crime or tension in the main city and have a population of at least 30,000.
No crime or tension in a city of at least 30,000 people
If you want to be free of crime and tension, you need to build a lot of watchtowers and battle centers, and make sure that other problems are controllable and that the population problem is not a big one.