On Labour Day, she also lauded the contribution of workers in the progress of the country and said they were the key to national development.
"Everyone will have to acknowledge that the plight of India's working class will improve by action and not by slogans and words alone, but by true conviction in helping accord equal rights and justice," she said in a statement.
She said it is because of the hard labour of workers that India is becoming self-reliant in every sphere. The workers are the key to development and also aid in the progress of society, she said.
Congress vice-president Rahul Gandhi tweeted, "On Labour Day, we pay tribute to the hard work of the true nation builders. In the success of their dreams lies the progress of our nation."
He also greeted the people of Gujarat and Maharashtra on the foundation day of their states.
International Workers' Day, also known as Labour Day, celebrates the spirit of labourers.