Amalgamation in politics means that two or more places or things join together to become one big thing. It's like when you and your friend decide to merge your toy boxes so you can both play with all the toys together.
In politics, it means that two or more cities, towns, or countries decide to join together and become one big place. For example, if two cities decide to merge, they might become one big city with one government instead of two smaller ones with their own separate governments. This can be helpful because it can save money and make things run more smoothly, but sometimes people don't like it because they feel like their voice isn't heard as much. So it's like when you and your friend both want to play with a different toy and you have to figure out how to share fairly.