Pakistan's first metro line began operations on Monday in the eastern city of Lahore.

 Stretching 27 kilometres and dotted with more than two dozen stations, the Chinese-backed "Orange Line" will cut travel time across the perennially congested city in Punjab province from two-and-a-half hours by bus to 45 minutes on the metro.

"This project will provide world-class facilities to the public in Lahore," Punjab's Chief Minister Usman Buzdar said during an inauguration ceremony on Sunday.

The line's opening follows years of delays, in a country that needs public transport and modern infrastructure.

The metro cost approximately 300 billion rupees ($1.8 billion). 

However, critics blasted the project for endangering numerous historical sites across Lahore.

Despite the delays and controversies, authorities are hopeful the new line will reduce traffic congestion in the city of more than 11 million, where commuters frequently spend hours in cars or buses daily due to grinding traffic.

Officials expect about 250,000 people will be able to travel on the metro system daily. Much of Pakistan suffers from poor public transport infrastructure making daily commutes in urban areas difficult and costly for many low-wage workers.

Beijing has been steadily pouring cash into Pakistan, investing more than $50 billion as part of the China-Pakistan Economic Corridor that has upgraded infrastructure, power and transport links across the country.

Chinese news agency Xinhua praised the opening of the metro line, calling it the beginning of "a new stage for the South Asian country in the public transportation sector".