Counterfeit medicines account for about 11 per cent of medicines in developing countries and are
likely responsible for the deaths of tens of thousands of children from diseases like malaria and pneumonia.
According to WHO, these medicines not only fail to treat or prevent diseases but can also cause serious illness or even death.
"Substandard and falsified medicines particularly affect the most vulnerable communities," said Tedros Adhanom Ghebreyesus, the WHO Director-General.
The report highlighted that since 2013, the WHO has received 1,500 reports of cases of substandard or falsified products. Of these, antimalarials and antibiotics are the most commonly reported.
About 4.5% of the drugs in the Indian market are substandard, according to surveys by the Central Drug Standard Control Organisation (CDSCO), the official regulatory authority.
The fake drugs market in India is likely to cross US$ 10 billion mark by 2017 from the current level of about worth US$ 4.25 billion, according to an ASSOCHAM recent analysis.
Substandard drugs also contribute to the growing threat of antibacterial resistance in the country; one that has doubled in the last five years in India, according to IndiaSpend.
Standard drugs could be three times more prevalent than what the government suggests, according to two recent studies.
A study published in the December 2015 edition of the Journal of Applied Pharmaceutical Science, found a sub-standardisation of 15.62% for diclofenac sodium, a popular painkiller.
"This is sad because many consumers shell out more for reputed brands, believing those products are better," said Ahmed Nawaz Khan, co-author and assistant professor Department of Pharmacy, Jaypee University of Information Technology, Solan.
According to the report there is clear evidence that resistance to the most important antimalarial medicine, artemisinin, first appeared in a part of the world where at one point between 38 and 90 per cent of the artemisinin medicines on the market were substandard or falsified.
The findings are part of WHO Global Surveillance and Monitoring System for substandard and falsified medical products. It is first time in 10 years that the WHO is publishing estimates on substandard and falsified medical products in low- and middle-income countries.