Sati describes how he once got a distributor-cum-manufacturer to induct him into the racket so he could understand its workings. He pretended to want fakes made of a common brand of painkiller.

From Delhi, they drove to a small manufacturing unit in Sonepat which already had moulds for the tablets, and paid cash in advance for a batch of 100,000. Then they went to a printer in Karnal, who had the design files required to print the strips. They tasked another man with collecting the tablets and delivering them in strips.

In Delhi, Sati had cardboard packaging printed, and stamps made to emboss batch numbers and expiry dates. In a few days his batch of fake medicine was ready. Sati burnt the lot and had the manufacturer raided; he was told he would be shot if he was ever seen in the manufacturer’s town.

An important step while getting fakes made, Sati says, is a question that the manufacturer asks: “Which do you want? Full-salt, half-salt or chalk-mitti?” That is, fakes with the stated amount of active ingredient, with only some of the active ingredient, or just chalk dust. Each has a different price.

According to Sati, the practice of adding a fraction of active ingredient to fakes began to be seen in India around 15 years ago, as drug controllers and consumers began to realise that there were fake medicines in the system. Manufacturers of fakes saw it as a way to protect themselves, as the medicines might have some effect and draw less attention. And if they were caught, it allowed them to claim that it was a case of production error rather than outright fakery.

Besides, the simplest tests to detect fakes are colorimetric ones, which detect the presence of an ingredient but not its concentration. So it was less likely that fakes with some amount of active ingredient would be found out. While this might work well for the manufacturers, it is bad for the patients – who receive sub-therapeutic doses, too low to properly treat their illnesses – and terrible from the perspective of antimicrobial resistance.

“Sub-therapeutic dosing, by definition, contributes to antimicrobial resistance,” says Elizabeth Pisani, an epidemiologist and a visiting senior research fellow at the Policy Institute, King’s College London.

“Bugs are mutating all the time,” she explains. Some of these mutations make the bugs slightly more resistant to drug treatment, but the mutants are usually at a disadvantage among non-mutants because it takes them more energy to reproduce.

Our antimicrobials work most effectively against the non-mutant versions, but a full therapeutic dose further ensures that slightly resistant versions are eliminated too. However, if you have only a fraction of the active ingredient, it’s going to knock out the susceptible ones first and there might not be enough left over to knock out the slightly resistant ones. “That creates elbow room for the slightly resistant ones to reproduce because the competition has been wiped out,” says Pisani. “And that’s how a mutant version becomes a dominant strain.”

She adds that falsified medicines with zero active ingredient can contribute to resistance too. People taking blanks will often switch to a next-line antimicrobial drug, thinking that what they’ve already taken was ineffective. Pathogens then get exposed to a drug that would ideally only be used on rarer, resistant infections.

What is usually measured in testing for fakes and substandards is the amount of active ingredient. But even when medicines contain the correct amount, not all of it may actually be available for absorption by the body. Pisani says the poor formulation of medicines probably greatly increases the proportion of drugs that are delivering sub-therapeutic doses.

All things considered, Pisani suspects that poor-quality medicines are a significant contributor to antimicrobial resistance. But while laboratory studies, modelling and common sense all point to the link between poor-quality medicine and resistance, it would be hard to study directly in humans. As Pisani puts it, “The way we would normally test those things is in a large human trial, and we can’t actually give people crap medicines, right?”

Yet, unintentionally, that’s exactly what’s happened in recent history.