From Activity 1, Angshu's mail states 'It's breezing now.' This describes the weather condition, for which 'it' is used (Use, point 6).
Class 6 › English Grammar and Composition › Chapter 7: Introductory 'There' & 'It' › Topic: Understanding the use of 'there' for existence, events, and quantities
Aligned to the NCTB national curriculum.