Dear Paramjeet,
EHS means Environment Health and Safety.
Companies opt for EMS and OHSAS Certifications as per ISO 14001 2004 and OHSAS 18001 2007 respectively.
The most important aspects are to identify applicable legal requirements, and set a procedure to comply them.
If any company has 100 % compliance to its legal requirements, it is 70% close to get the Certifications.
Once legal requirements are done, Hazard Identification and Risk Assessment under OHSAS 18001 and Aspect Identification and Impact assessment is to be done under ISO 14001.
Once these studies are done the improvement plans to reduce risks above acceptable level, and redcution of adverse impacts on environment are to be taken through objectives and targets.
Pl study these standards and come back if you need any more information.
Thanks &Regards,
Sudhir