SIKH

Years ago, in the book “Bhowani Junction” (which was made into a film and shot in Lahore), I read about Sikhs not being allowed to eat “halal” meat. I thought the writer might have made a mistake, since Sikhs (believing in one God) are closer to Muslims than Hindus. But now I have come across someone else saying the same thing, in fact it is Shiromani Gurdwara Parbandhak Committee (SGPC), the supreme temporal body of the Sikhs. In today’s Times of India, there is an article entitled “Those who trim hair, beard are not true Sikhs: SGPC”,. I have no quarrel with that, since this is the only visible feature of Sikhs which makes them stand out from others.. But then the article says, (and this I cannot understand), “Sikhs should abstain from liquor, cigar and halal meat”.
Of course, what they eat or drink is their own business, but why this ban on halal meat? If there’s a Sikh scholar who’s reading this, I’ll be grateful if he can explain this peculiar tenet for being a true Sikh.