Sanjay I had my instincts about this one but looked it up to be sure. It is a technique of winding two coils that are wound in the opposite sense to each other to avoid picking up interference. It is a well know technique used in Guitar pickups to enable the pickup to be sensitive to the guitar strings vibrations but not to any hum fields that are around it. There's a good article herehttps://www.sweetwater.com/insync/what-are-rwrp-pickups/I've also seen this used to make non-inductive resistors. Half the wire is wound in one direction, then looped around a pin in the former (usually a ceramic tube) and the rest wound in the opposite direction. The inductances then cancel out.
