Regarding Fixed tenure basis job in psu

Legal advice and legal services Extension of contract employee in Govt of India PSU I joined a govt of India psu in Delhi in March 2017 as a field engineer initially the contract is for 2 years upto 2011. But they further extended the contract agreement for 1 year as the project is still going on. At the first phase of the project is completed they terminated all of us in August 2019 ( there are 50 contract employee) We already approach the management many time in the past for providing continue the contract on other projects of the company.In this psu there are 5000 thousand field Engineer and Field Supervisors on contract basis and they have only 5000-6000 thousand Regular Employees. There all things like projects work ,project profits all depend on FTB Engineers, But still they terminate the employee and recuite the new FTB Engineers. I request u to suggest how can I Regular contact on PSU. Please suggest what legal action we can take in this matter and ask for permanent position.