Here are a few options, depending on the level of formality you need:
Most Direct:
- “Gadkari Files Defamation Suit Regarding E20 Fuel Misinformation”
Most Formal/Legal:
- “Union Minister Gadkari Initiates Legal Proceedings Over E20 Fuel Misinformation”
Standard Professional:
- “Gadkari Takes Legal Action Over Alleged Misinformation Concerning E20 Fuel”
Recommendation: The first option, “Gadkari Files Defamation Suit Regarding E20 Fuel Misinformation,” is the most professional and standard choice for a news headline.