Nagar Nigam works in the city because population is moreExplanation'-

there are exceptions to that, as previouslynagarpalikas were constituted in urban centers withpopulationover 20,000 so all the urban bodies which were previously classified asNagar palikawere reclassified asNagar palikaeven if theirpopulationwas under 100,000

Nagar Palika : Municipality

Nagar Nigam : Municipal Corporation

Nagar Parishad : City Council

InIndia, a Nagar Palika or Municipality or Nagar Nigam is an urban local body that administers a city of population 100,000 or more. However, there are exceptions to that, as previously nagar palikas were constituted in urban centers with population over 20,000 so all the urban bodies which were previously classified as Nagar palika were reclassified as Nagar palika even if their population was under 100,000. Under the Panchayati Raj system, it interacts directly with the state government, though it is administratively part of the district it is located in. Generally smaller district cities and bigger towns have a Nagar palika. Nagar palikas are also a form of local self-government, entrusted with some duties and responsibilities, as enshrined and guided upon by the Constitutional (74th Amendment)Act,1992.

An urban local body that administers with more than 15,000 and less than 25,000 inhabitants is classified as a "nagar panchayat" or "nagar parishad".

The basic difference is in the population [number of people] and type of area [rural, suburb, city].