AbstractNew Delhi's climate is a difficult climate to design for, being composite in nature: it experiences a dry-hot summer with temperatures up to 45°C and winters with temperatures down to 3°C and an in-between hot-humid season. The city of Delhi has a long continuous history and each stage of its development, from medieval times through the colonial period until the New Delhi of today, is to be found intact as a standing record. Each period of the city's historical development has been marked by a distinct pattern of urban growth. It is interesting to note that while climate has been an important and constant factor, the overlaying of cultural, socio-economic and technological changes resulted in widely different forms of urban structure being adopted.The changes in housing form that occurred through the three stages of the city's development were analysed systematically keeping climate as a constant factor with the variables of construction, urban structure, social patterns and symbolic language being seen as dynamic counterpoints to understand the resultant built form. This was used to identify principles of housing design of the traditional and colonial forms of housing which could be adopted to serve present-day needs and to identify those irreversible developments which make our present situation significantly different from the past.The lessons learnt from the analysis commended: (a) from the traditional housing form — the value of a tightly knit urban structure that shelters both outdoor and indoor spaces, and the street and court as socially meaningful spatial configurations; (b) from the colonial example — the use of vegetation as a microclimate modifier combined with a relaxation of built density to respond more favourably to humid and cold seasons. The factors that distinguish the present situation from the traditional and colonial situations are motorized vehicular access, relatively low mass of building construction materials and techniques, and the pressure on land causing high population densities and high-rise construction.The lessons of thie research are applied to two housing design projects for the middle-income group category of housing. These architectural solutions, which aim at optimizing environmental qualities for housing along with climatic comfort and energy utilization, suggest some limits of density and land-utilization beyond which environmental quality and energy efficiency would decline. It is recommended that such design exercises be undertaken to establish both the lower and upper limits of density and land-utilization for housing so as to provide a more holistic basis for fixing town planning norms.