if police is blocking access obtain court orders to direct police to permit access to your property as you have been in open , hostile uninterrupted possession for 40 years 

What the  police is doing amounts of interference in administration of justice by Court. Police are liable for contempt proceedings. Unless there is specific order by Court in which  dispute is pending, police has no power to meddle in the  matter. Approach the  Court, file an application  under Section 151 of Civil Procedure Code, 1908 seeking restraining police from blocking access as the  matter is civil dispute.

- Since, the matter is pending before the Court , hence the said act of police official is against the law. 

- Hence, you can move an application for contempt before the same court against that police . 

- Further , you can move also an application before the said court for injunction against all the parties in the suit , so that none can interfere in the said property. 

Hi, The police has no authority to block the access. As the matter is pending adjudication before the Court. You can file necessary application for the access.

Challenge the order of police for blocking the same illegally

If police is blocking the access without any valid reason you may approach the higher police officer and look for solution locally,  if that's also not fetching the desired relief then you may file a permanent injunction suit against the concerned police for remedy and relief. 

You can file for Injunction or Caveat against that officer.