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One of the magento based website had strange issue. All rules in the admin > Promtions > Catalog Price Rules were inactive. But still some products were displaying as sale items. So ran mysql code listed below to find out what was happening.
From today onwards I am going to apply these rules to fix issues with SEO.
Magento admin / System / configuration / General / Web / Auto-redirect to Base URL / Yes (301 Moved Permanently)
Also, add robots.txt file with below content.