Need to understand taxation with regards to indemnity

"Taxes and Surcharges. Purchaser acknowledges, understands and agrees that all charges for Services provided hereunder are exclusive of any applicable federal, state or local use, excise, gross receipts, sales and privilege taxes, duties, fees, tax-like charges, payphone or other surcharges or similar liabilities (other than general income or property taxes), hereinafter referred to as "Additional Charges," whether charged to or against S2R or Purchaser because of Services provided to Purchaser. Purchaser shall pay all Additional Charges in addition to all other charges provided for herein. Purchaser will not be liable for exempted Additional Charges in a jurisdiction assessing an Additional Charges if Purchaser provides S2R with a legally-sufficient exemption certificate in that jurisdiction before Services are rendered. S2Rshall indemnify, hold harmless and defend Purchaser from and against any and all actions, suits, proceedings, administrative charges, liens, liabilities, claims, assessments,  fees, interest, and penalties arising out of or in connection with S2R's failure to remit tax to authorities, in a timely manner, any Additional Charges. In the event Purchaser is required by law to deduct or withhold any taxes from any sum payable to S2R under this Agreement, Purchaser shall make such deduction or withholding as required and the amount payable to S2R shall be decreased by such amount"

We are a USA Based Telecom Services Company providing this Services in USD, Having No PE in India 
1. We need to understand the application of Indemnity in this taxation clause and how much of Holding Tax Applicable on this?
2. What is the Implication of DTAA between India & USA with regards to this clause?
3. What happens if US Company Provides the Service to a Company In India and India Entity resells the same in INR?