None of them caused any casualities or any damage to infrastructure. As we have multi layered defense system with L70 and Zu23 for very short range Defense agains drones and UAV, Spyder for Short Range, Akash for Medium range, s400 for Long range and high value target, exact kill rate of Guns are unknown. In press briefing, officials said that these were so effective against drones.

That's very impressive, especially at low cost.

Yes, Cost is the main factor, one cannot use expensive air defense to shot down drones that are relatively cheap.