She also said that it will stop creation of a global mega monopoly on seeds and agri-chemicals.
"This is a great victory for our farmers, for citizens of India, as now the CCI has stopped the poison makers - Monsanto and Bayer from merging in India.
All over the world, Monsanto and Bayer seek to control each link of the food-health chain.
"From the seeds to pesticides to pharmaceuticals, they have a grand design to create a new 'Company Raj' which profits from farmers' suicides, disease and finally death.
More From This Section
The Competition Commission of India (CCI) has asked for filing of fresh application with respect to German major Bayer AGs proposed USD 66 billion buyout of Monsanto.
The deal, announced in September 2016, would create the world's biggest seed and pesticide firm.
"Navdanya welcomes the CCI's decision to cancel the merger of Monsanto-Bayer in India. This order comes as relief for millions of farmers and activist who with us have been asking the CCI to probe the matter and stop the creation of a global mega monopoly on seeds and agri-chemicals," a statement said.