This is how the story goes: one official at the time, who was a staunch education advocate, would order his staff to patrol the city late at night. If they saw students burning the midnight oil, so to speak, they would offer them oil for their lamps as a gesture of encouragement for their diligence.

But before I go any further on the linguistic value of “add oil”, which has recently (and unfortunately) become a highly sensitive political phrase when used alongside “Hong Kong”, I want to emphasise that this is a cultural discussion, not a political one.

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A similar thing took place in Shanghai during the recent months of lockdown, and probably in many more Chinese cities on a smaller scale.

Perhaps most controversially, “add oil” was used by demonstrators during the 2019 anti-government protests when they chanted “Hong Kong, add oil”.

If “add oil” can be used alongside other Chinese city names, then it seems the only problematic words of the phrase are, in fact, “Hong Kong”.

Well, if Hong Kong is not allowed to add oil any more, what can locals say to offer words of encouragement to one another?

Hong Kong people are highly ingenious and always find clever ways around things. Maybe we can substitute “oil” with “gas”, “water”, or popular dim sum dishes like har gau and siu mai.

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In an ideal world, we shouldn’t put a blanket ban on the phrase “Hong Kong, add oil” just because it was hijacked by protesters. Allowing people to use the phrase won’t make the city any less safe or people any less patriotic.

The core meaning of “add oil” is simple and straightforward. It encourages people to keep going, to never give up, to stay strong and to remain positive. Isn’t this what the Hong Kong spirit is all about?

Any phrase is capable of inciting others to break the law, depending on the context and circumstances in which it’s used. We wouldn’t ban knives just because some people use them to hurt others, would we?

During the 2019 protests in Hong Kong, people used a coded phrase “going shopping” to say they were gathering to protest to circumvent detection. If we apply the same logic, are we not allowed to say we are going shopping ever again?

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We should have the maturity and intelligence to differentiate intent, and we certainly do in Hong Kong. More people should be made aware that the phrase “add oil” has a long, interesting history illustrating how the government supported education and students hundreds of years ago.

Chinese people have a habit of labelling things. Labelling the number four as unlucky is a classic example. Since its Chinese pronunciation sounds the same as the word for “death”, some people avoid this number like the plague.

Hongkongers should retake ownership of the phrase “Hong Kong, add oil” and perhaps add whatever they deem necessary to give each other a much-needed boost after two years of Covid-19 and economic downturn.

With the unrelenting threat of Covid-19 still raging, as well as high unemployment and economic woes, Hong Kong needs to add even more oil, as well as peace and love – now more than ever.

Luisa Tam is a Post correspondent who also hosts video tutorials on Cantonese language that are now part of Cathay Pacific’s in-flight entertainment programme