Then & Now | How Hong Kong buildings kept cool before air conditioning by copying India – deep verandas, high ceilings, chick blinds and shutters

Sustainability has become a buzzword in recent years and more-form-than-substance “green initiatives” inevitably lead to accusations of “greenwashing”. But how did buildings in the past help define an earlier era’s notions of practical sustainability?

Above all else, the aim in Hong Kong and elsewhere in maritime Asia was to keep a building’s occupants sustainably cool – and therefore healthy, a vital consideration in the disease-prone tropics – in the days before mechanical cooling methods, such as electric fans, were invented, and widely introduced. Air conditioning – and the far-reaching transformations that invention brought – was another century away.

In newly established cities, such as 1840s Hong Kong, practical examples from elsewhere were readily copied. After all, why reinvent the wheel? Surprising as it may seem to many today, the architectural exemplar for early Hong Kong was Calcutta, and buildings elsewhere in Bengal.

The reasons were manifold, and fundamentally practical; Calcutta – then – was the major external trading partner for the Canton delta, and for a cosmopolitan array of merchants, constant travel there made for familiarity.

Both cities lie on almost the same latitude, thus climatic conditions are similar: a cool, dry few months in the winter, with a brief period when both places are actually cold, followed by several months of scorching heat, high humidity, fairly heavy, regular rainfall, and intermittent tropical depressions in the summer – known as cyclones in the Bay of Bengal, and typhoons in East Asia.