Jharia is famous for its rich coal resources, used to make coke. The coal field lies in the Damodar River Valley and covers about 110 square miles (280 square km) and produces bituminous coal suitable for coke. Hence, the correct option is (d).

Jharia in Jharkhand is chiefly known for coal mining.

Jharia, located in the Dhanbad district of Jharkhand, is one of the largest coal mining areas in India. It is famous for its vast reserves of high-quality coal and is considered the lifeline of the region's economy. The town is situated in the Damodar Valley, which is known for its rich coal deposits.

Coal Reserves in Jharia:

Jharia coalfield is estimated to have reserves of about 19.4 billion tonnes of coal. These reserves are spread over an area of approximately 450 square kilometers. The coal extracted from this region is primarily bituminous coal, which is widely used in industries such as power generation, steel production, and cement manufacturing.

Importance of Jharia Coal:

1. Power Generation: The coal from Jharia is used extensively for power generation in thermal power plants. It provides a significant portion of the fuel required for electricity production in the region.

2. Steel Production: Jharia coal is also crucial for the production of steel. The coking coal extracted from this region is used in blast furnaces to produce coke, a key ingredient in the steelmaking process.

3. Domestic and Industrial Use: Apart from power generation and steel production, Jharia coal is also utilized for domestic and industrial purposes. It is used as a fuel in households and small-scale industries, providing a source of livelihood for many people in the area.

Challenges Faced:

Despite its immense coal reserves, Jharia faces several challenges due to extensive mining activities. The underground fires that have been burning for decades pose a significant threat to the environment and the health of the local population. These fires, caused by the ignition of coal seams, have resulted in land subsidence, sinkholes, and the release of toxic gases.

The underground fires have led to the displacement of thousands of people from their homes, as entire neighborhoods have been engulfed by the flames. Efforts are being made by the government and mining companies to extinguish these fires and rehabilitate the affected population.

In conclusion, Jharia in Jharkhand is chiefly known for its vast reserves of coal. The coal mining activities in this region play a crucial role in the economic development of the area, providing fuel for power generation, steel production, and domestic use. However, the region also faces significant challenges due to underground fires and their impact on the environment and the local population.