Constable Aafaq was patrolling the North-Eastern Railways (NER) station here when he noticed two men whose movements he found suspicious, D.K. Upadhyaya, inspector of Government Railway Police (GRP), Charbagh, told IANS.
Upon being challenged by the constable, one of the men shot at Aafaq twice before they tried to flee the scene, Upadhyaya said.
"The constable managed to catch hold of one of the attackers while the other fled," he said.
The injured constable has been admitted to a hospital; he is serious but out of danger.
The attacker who was nabbed by the policeman has been identified as Rohit, a resident of Faizabad district. There have been more than a dozen attacks on policemen in the state capital in the last five years.