Section 153(2) in The Coal Mines Regulations, 2017
(2)For the purposes of securing adequate ventilation as specified in sub-regulation (1), the owner, agent and manager shall ensure that-(a)in every ventilating district, not less than six cubic meters per minute of air per person employed in the district on the largest shift or not less than 2.5 cubic meters per minute of air per tonne of daily output, whichever is larger, passes along the last ventilation connection in the district which means the in-bye most gallery in the district along which the air passes;(b)at every place in the mine where persons are required to work or pass, the air does not contain less than 19 per cent. of oxygen or more than 0.5 per cent. of carbon dioxide or any noxious gas in quantity likely to affect the health of any person;(c)the percentage of inflammable gas does not exceed 0.75 in the general body of the return air of any ventilating district and 1.25 in any place in the mine;(d)the wet bulb temperature in any working place does not exceed 33.5 degrees centigrade, and where the wet bulb temperature exceeds 30.5 degrees centigrade, arrangements are made to ventilate the same with a current of air moving at a speed of not less than one meter per second; and(e)for ensuring compliance with the provisions of clauses (b), (c) and (d) of this sub-regulation, air samples and temperature readings shall be taken at least once in every thirty days and the results shall be recorded in a bound paged book kept for the purpose:Provided that at any mine or part, where special conditions exist, the Chief Inspector may, by an order in writing and subject to such conditions as he may specify therein, approve a ventilation scheme in variance with the aforesaid provisions.
