You start out as a single person running around an urban area and looking for other people to join you. Evidently, your character is pretty charismatic: when you run into a neutral NPC you quickly convince them to become a member of your party. The goal is to create the biggest crowd on the map outnumbering the crowds of all the other players in a short period of time.
CrowdCity.io is all about bringing people together. To assimilate a new member into your little army all you need to do is approach a random pedestrian of a neutral color. They will automatically join you becoming the same color as you. The more people you run into, the bigger your crowd becomes, but you should always be aware of other players: if their group has more members, yours will be consumed completely and you will have to start from scratch. The good news is, you can do the same as long as you outnumber the opponent.
Play CrowdCity.io, become the leader the people are looking for and create the biggest following on the map. Prove that your crowd is the strongest in the city!