Amid tight security, the sixth batch of over 6,300 Amarnath pilgrims on Tuesday left for the 3,880-meter-high cave shrine of Amarnath in south Kashmir, officials said. A total of 6,351 pilgrims left the Bhagwati Nagar Yatri Niwas here in a convoy of 239 vehicles amid heavy security of CRPF, the officials said.