Permanent establishment rules define fixed place and dependent agent thresholds determining tax presence under the DTAA. The Article defines permanent establishment as a fixed place of business and enumerates examples (place of management, branch, office, factory, workshop, extraction sites, installations, farms, sales outlets). It excludes facilities used solely for storage, display, stock maintenance for processing, purchasing, information collection, advertising, research or preparatory/auxiliary activities. Construction or installation projects constitute a permanent establishment only if exceeding 12 months, subject to mutual agreement. Agency rules attribute a permanent establishment where a non independent agent habitually concludes contracts, secures orders almost exclusively, maintains stock for deliveries, or manufactures/processes for the enterprise, while independent agents acting in the ordinary course do not create a permanent establishment.