Assessment of urban area dynamics in world's second largest megacity at sub-city (district) level during 1973–2016 along with regional planning

Unplanned and rapid urbanization leads to land-use heterogeneity, which is difficult to be captured in detail through city-level panoramic studies and thus warrants sub-city level assessment. The current study quantifies and assesses district-level urbanization in the world's second largest megacity, Delhi (India). The study extends on temporal scale from year 1973–2016 and utilizes urban expansion intensity, gravity centre model and landscape expansion index and regional context of planning. The findings of the present research are aligned with Master Plan of Delhi. The spatial patterns and level of urbanization is different in districts, thus, zonation of 11 districts into four categories is done for both individual and conjoint planning. The urban expansion in Delhi is observed mainly due to edge-expansion followed by outlying and infill. A tremendous increase in the number of urban clusters at outskirts is observed during year 1999–2005 and in subsequent years, expansion is observed in the area of existing urban clusters. The regions expanded by infill have shown congested and compact urban form. Over the years, urban land gravity centres of districts are found to move outwards in four directions whereas that of the city is moving in north-west direction and is expected to move in north-west or south-west in future. The more developed satellite towns are found in close proximity of the more urbanized districts of Delhi, thus indicating spatially distorted planning in Delhi national capital region (NCR). The findings are in accordance to the census data which has been used for validation. With unprecedented increasing urbanization across the world, this research has wider scope with various global cities, analysed at sub-city level to examine their spatial planning disparities and promote equitable development.