Regarding navin parti land

Navin parti is a land that remains unallocated after the process of land consolidation, which is aimed at reorganizing agricultural land. 

The land remains the property of the Gaon Sabha (village council) and is reserved for public uses. 

Therefore your house built on Navin parti land is illegal hence the revenue department has full rights to demolish the illegal structure constructed over the newly designated waste or unused land left over after land consolidation efforts, vested in the Gaon Sabha (village council) for public purposes, and not categorized under specific rules for public or private use. 

Have they issued any notice to you to remove the structure nbuilt on the said land?

If yes, then you may take precautions accordingly so that you don't suffer heavy damage or loss. 

Therefore you may please note that you cannot simply construct on 'Navin Parti' land in Uttar Pradesh; it is typically reserved for public use and is not a plot for private construction. To build, you would need to pursue a complex process of obtaining official approval for land conversion and ensure the land is legally reclassified from 'Navin Parti' (a type of land for specific public or state purposes) to a residential or other suitable category for construction, which is often a lengthy and difficult process.

The only threat is to file a suit. As such, you have option to defend on merits if there is no wrongdoing and to make amends to the extend you have erred.

My home is total of 1700 sq feet out of which 200 sq feet is coming in the Navin parti. As it is built by my great grandfather in 1990 and he didn't knew about it. Now what should I do ?

Can I apply IPC 67 A as I belong to the same gram sabha and we don't have another house and we are not bhu mafiyas.

It is all done by opposite party that has also occupied 4 dismil land of Navin parti. And Gram pradhan and lekhpal both are against me.

The law has been explained to you in this regard.

If your neighbors or others are doing a wrong thing, you cannot take shelter for your wrong doings on that basis.

No criminal complaint is also maintainable 

Yes, there is no eaquality in illegality. However, if a suit filed, you may rely upon adverse possession in defence.