27.
The answer is: C
Explanation
The correct option is C: Any solid, liquid or gaseous substance present in such concentration as may be, or tend to be, injurious to environment.
This is the definition of 'environmental pollutant' given in the Environment (Protection) Act, 1986, Section 2(b). The Act aims to protect and improve the quality of the environment and prevent, control and abate environmental pollution. The Act empowers the Central Government and the Pollution Control Boards to set standards and regulate the emission or discharge of environmental pollutants by various sources.