On the international level, heritage is considered an essential element for the sustainable development of a country. In South Asian countries such as Pakistan, India, and Bangladesh, historic cities struggle to preserve their built heritage, due to rapid urbanisation and changing contemporary urban and architectural requirements. This contribution elaborates on the effects of urbanisation, and city development on the protected heritage of Karachi, Pakistan. The city developed in the 19th century from a mud-fortified small town along the Lyari river to become one of the busiest ports of the Indian subcontinent under British rule. Karachi has now become a metropolitan city with more than sixteen million inhabitants. Due to the accelerated rate of urbanisation and trade activities, Karachi has become Pakistan’s economic capital, resulting in the oblivion of its historical sites. Most of the city’s historic sites are in a state of dereliction, from over- or under-programming, or even under the threat of demolition. The paper focuses on the present condition of a British-era protected-heritage site through a literature review and fieldwork (mapping, drawing, archival research, interviews, photographic surveys, etc.), carried out during 2019 and 2020. The first author conducted site visits to photograph buildings and interview their users to gather feedback on how they perceive the current state of these buildings. The data were analysed to investigate how many buildings from Karachi’s British era with protected status have been demolished or are at risk of demolition. At the heart of the article is the Saddar Bazar Quarter in Karachi and its historical, social, cultural, and economic importance in the city from the British period until the present. The analysis will lead the discussion on what potential these sites/buildings hold, and how to make their preservation possible and withstand the uncurbed urbanisation and the threat of land development. Through discussion, we will focus on the social, cultural and economic aspects which the area and the buildings from the British period hold, and which can be useful in the future for the continuation of the Saddar Bazaar Quarter (SBQ), the historic urban landscape (HUL) and the heritage buildings.