The correct option, 1 and 2 only, is valid because Indian coal, particularly the types found in the country's major coalfields, is characterized by a high ash content, with many varieties containing over 30% ash. Additionally, Indian coal typically has a low sulfur content, which is beneficial for reducing harmful emissions during combustion. However, it is incorrect to say that Indian coal has a low ash fusion temperature; in fact, many coals have a relatively high fusion temperature, making them less suitable for some metallurgical processes. This understanding is crucial for evaluating the suitability of coal for various energy and industrial applications, as outlined in standard reference materials for UPSC preparation.