Consider the following statements : 1. Coal ash contains arsenic, lead and mercury. 2. Coal-fired power plants release sulphur dioxide and oxides of nitrogen into the environment. 3. High ash content is observed in Indian coal. Which of the statements given above is/are correct?

Option (D) is correct because coal ash contains toxic heavy metals like arsenic, lead, and mercury, coal combustion is a major source of SO2 and NOx emissions, and Indian coal is geologically characterized by a high ash content (typically 35-45%). Option (B) is the most tempting wrong choice for those who might incorrectly assume fly ash is chemically inert, whereas it is actually a significant source of hazardous trace elements. The core concept being tested is the environmental impact of thermal power generation and the specific mineralogical properties of Indian coal.