Kya hai Fair Use aur Its Scope in India?

Bhai log, main to confused ho raha hoon. Mere professor ne ek example diya ki ek author ne ek article likha tha, jisme kai lines copy-paste ki gayi thi. Lekin author ne yeh bhi likh diya ki yeh lines use ke liye permit thi - iska matlab kya hai? Kya hum bhi article likh ke kisi dainik patrika se lines copy-paste kar sakte hain aur yeh fair use kaha jaayega? Main socha ki fair use ka scope toh badi cheez hai, lekin kya yeh kisi bhi situation mein apply hoga? Aur kya yeh toh copyright law ke against hai? Badi confusion hai bhai log, koi please help karayega.