Unauthorized colonies is the name given to hundreds of residential/industrial colonies that have come up in Delhi without DDA's authorization and are not in regulation of the Delhi master plan regulations. Due to British colonization, the earlier programs of the British colonial rules were imposed on India by nationalist leaders and lawyers at the time of Independence. The result was that just like the west, it was presumed that India too would break into an industrialized nation by borrowing the development plans from the developed nation. The result was that pockets of development were created in the form of cities while other parts were rural in nature. A large population settled in the form of slums in the cities and the another large portion of the population with better means and economic, political capacity bought plots in unauthorized colonies, while the elite used to live in the beautiful authorized part of the city. Development was greater in terms of Delhi as being directly into the hands of Centre's rule. So unauthorized colonies too formed due to the underprivileged urban middle class just like in the case of slums where the urban poor started residing for the desire of better prospects in future. The unauthorized colonies grew faster in sizes and capacity supporting even larger population than the slums and slums were already supporting more population than the unauthorized colonies. Soon, the unauthorized colonies are able to get resources and civic needs like water supply, sewerage and others into it. And many rich and affluent people too were residing in the unauthorized colonies. Although the unauthorized colonies have a plot buying and renting system, the buying selling is done or carried out by a "power of attorney" recognized by law courts. The houses in unauthorized colonies are constructed of permanent materials like cement, bricks, tmt bars, etc rather than temporary materials as in the case of slums. So, unauthorized colonies having better economic and political prospects get authorization from DDA. Houses made in unauthorized colonies are even made on government land but overtaken by DDA and so do not get authorization. Land market conditions created by property agents is the main reason for the coming up of large no. of unauthorized colonies. As of 2011, the total population of Delhi is 16.75 million, out of which 0.42 were in rural areas and 16.33 were in urban areas.
It can be said that just after the independence, development has been mostly focussed on the urban areas in Delhi. So, a large number of people went from rural areas to urban areas in search of job and better future prospects. they formed either the slum areas or the people with better economic and political capacity settled in unauthorised colonies. Unauthorised colonies grew faster than the slums or the authorised areas. Delhi had a influx of population not only from rural areas but also from other parts of the country and so the population in unautorised colonies grew rapidly in Delhi. Politics too have a great role in unauthorised colonies getting authorisation.