What is the main reason that local leaders sometimes create special districts?

They give particular administrations that are not being provided by existing broadly useful governments. Most play out a solitary capacity, however in a few occasions, their empowering enactment enables them to give a few, generally related, sorts of administrations. The administrations given by these regions run from such fundamental social needs as healing facilities and fire security, to the less prominent errands of mosquito reduction and upkeep of burial grounds. In-short, they bring the government closer to the people at the "grass-root" level.

following type of cultural development caused people to want and buy new products on the market :

industrialization