How do I catch ants in countries with densely packed cities?

This is from Bangladesh in the continent of Asia.

I wanna know people who live in densely population countries, how do you catch ants? Normally there is so much options in getting ants like buying, shipping from abroad and all. But with a country like mine it's impossible and ant enthusiasts in here are mostly negligible if I say so.

So how do some of you all in other dense population city or countries you all live in catch ant queens?