Silver Jubilee marks a 25th anniversary. The anniversary celebrations can be of a wedding anniversary, the 25th year of a monarch's reign or anything that has completed or is entering a 25-year mark. From Wikipedia
The Silver Jubilee edition of the IIFA Awards celebrated in Jaipur saw 'Laapataa Ladies' dominate, while Kartik Aaryan and Nitanshi Goel's acting wins faced public criticism.