The common reason for such bans is that various tests have found excess quantities of lead and MSG (Monosodium-glutamate) in Maggi.
Why exactly are these substances bad for the human body?
HuffPost India spoke with Amit Khurana, project manager for food safety and toxins at the New Delhi-based Centre For Science and Environment, to find out how lead and MSG harm our bodies.
Lead is a heavy metal, Khurana said, which the body does not excrete, but rather it gets accumulated in the body.
This heavy metal affects multiple body systems but is especially harmful for the liver and kidney, said the food safety expert. Infants and pregnant women are particularly vulnerable to lead because it harms the central nervous system in children.
READ: Delhi Bans Maggi Noodles
The World Health Organisation also confirms that lead is particularly harmful for children: WHO finds that childhood lead exposure is estimated to contribute to about 600,000 new cases of children developing intellectual disabilities every year, and it estimated that lead exposure accounts for 143,000 deaths per year with the highest burden in developing regions.
"There is no known level of lead exposure that is considered safe," according to WHO. "Lead poisoning is entirely preventable."
The long-term impacts of MSG are still debated among doctors, Khurana said, but in the short-term it can cause hyper-tension, palpitations and headaches.
Food safety regulations in India require manufacturers to disclose whether MSG has been used on the product's package.
Khurana also explained food safety regulations do not allow MSG to be added to pasta and noodles, but it can be used in seasoning, which in this case would be the masala of the Maggi noodles. It is unclear, however, whether the MSG found in the Uttarakhand tested samples was in the noodles or the masala.
So far, the extent of the problem is also ambiguous. While Maggi noodles has been banned in Delhi and Uttarakhand, Maharashtra and Goa have found it to be safe. This could mean that only some batches of Maggi have excess lead and MSG.
Khurana said that state governments, which are testing Maggi, need to go public with the details of their findings so that people can understand the extent of the problem and the health concerns.
The expert also said the Maggi controversy only highlighted the lax standards of safety checks and labelling enforced for packaged goods in India.