The Council of Scientific and Industrial Research-National Environmental Engineering Institute (CSIR-NEERI) has conducted a study with respect to air pollution caused by stone crushing units in Tamil Nadu and concluded that there is no need to prescribe any distance criteria between two units, Advocate General R. Shunmugasundaram told the Madras High Court on Monday.

Appearing before Acting Chief Justice T. Raja and Justice D. Bharatha Chakravarthy, the A-G said, CSIR-NEERI had prescribed a safety distance of 500 metres only between the stone crushing units and national/State highways, inhabited sites, educational institutions, public offices, places of religious importance and so on in order to avoid the influence of dust emission.