Does ESI follow CGHS(CENTRAL GOVT. HEALTH SCHEME ) rules or any other?

Hi All, I would like to know how does ESI department work on reimbursement process. Which type of rules they follow?
Does ESI follow CGHS(CENTRAL GOVT. HEALTH SCHEME ) rules or any other?

ESIC allow the members to take treatment from outside (when the ESIC is unable to provide the specific treatment by its own), subject to panel doctor and AMO recommendation, and in that case they settle the bills either direct with the hospital/ dispensary or reimburse the same after payment through AMO office, but everything is possible with prior approval of Panel doctor / AMO approval only

ESI follow ESI Rules For Reimbursement. If you want to know about them see this Employees State Insurance or ESI Act, Rules, Forms, Returns : Simplified: Procedure of Making an ESI Claim