The camera is looking west over the Causeway Bay Typhoon Shelter and the largely vacant Wanchai reclamation. The presence and absence of buildings on the left side of the photo helps date it. The Excelsior Hotel (completed 1973) is the most prominent building. Just visible behind and above it is the World Trade Centre (completed November 1975).
A bit further down Gloucester Road towards Central, the British-American Tobacco Factory or its replacement, Elizabeth House, should be visible, but neither is seen. That’s probably because the Tobacco Factory had been demolished, but construction of Elizabeth House hadn’t reached a height visible from this angle. The Tobacco Factory was under demolition in February 1974 (1), the site was cleared but undeveloped in 1976 (2), and Elizabeth House was completed on 27 November 1978. Assuming a huge project such as Elizabeth House would have been visible at least one year before completion, the photo must have been taken in 1977 at the latest.
Therefore, the date range for this slide is between 1975 and 1977.
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