Four Indian pugilists will be seen in action in the pre-quarterfinals of the World Boxing Championships in Almaty, Kazakhstan today.In the 49kg category, Thokchom Nanao Singh will slug it out against Anthony Rivera Chacon of Puerto Rico, while Shiva Thapa will box against Alberto Milan of Argentina in the 56kg section.Manoj Kumar will clash with Canadian Yves Ulysse in the 64kg division, with Manpreet Singh taking on world number one and Olympic bronze medalist Teymur Mammadov of Azerbaijan in the 91kg section.Yesterday, Olympian Sumit Sangwan in 81kg category and Vikash Malik in 60kg category entered the pre-quarterfinals of the championships.