Dominating the region until the establishment, in 1911, of New Delhi as the new capital of British India (replacing Calcutta) Shahjahanabad (also referred to as Old Delhi or the walled city) is formed by a tightly knit conglomeration of buildings, internal courtyards and places. The whole city was divided into neighborhoods, mohullas, based on social and economic hierarchies. The ‘traditional’ or ‘indigenous’ dwellings, havelis – neighborhood-like mansion buildings, built around courtyards and often richly embellished were complex clusters of buildings indistinguishable from the urban fabric of the city. By the mid 19th century unable to support the lavish lifestyle of the mansions many owners decided to subdivide, sell or rent parts of their plots which created a new denser neighborhood within the historic structures.
… prospering entrepreneurs and traders rushed to rebuild residential structures, shops, and workshops from old abandoned or disused haveli buildings. … On small lots carved from the old large haveli, merchants built new, redefined haveli consisting of a single central courtyard with rooms all around. Smaller and more modest in design, the redefined “traditional” house was rational, efficient, and built with new materials and technology. … In colloquial usage, the word haveli in Delhi has remained a signature of traditional aristocratic living. However, in its many variations the haveli was not a timeless or changeless house form. From princely mansion to modest dwelling and then into a tenement house or a more rational and efficiently design house, the haveli has undergone a variety of metamorphoses.
This ‘metamorphosis’ happened principally within the walled boundary and despite removal of large sections of the original enclosing wall Old Delhi remains circumscribed and held in by major roadways which despite the incredible congestion and overcrowding remains a thriving business centre for India nationally and internationally.
 Hosagrahar, J. Mansions to Margins: Modernity and the Domestic Landscapes of Historic Delhi, 1847 – 1910. Journal of the Society of Architectural Historians, Vol. 60, No.1 (Mar.,2001), pp. 38 – 42. Published by the University California Press