* [[Timeline of pollution]]

* [[Timeline of pollution in Delhi]] (Last request by Vipul added) (Column distribution rearranged)

* [[Timeline of cloud computing]] (returned with feedback)

* [[Timeline of mobile telephony]] (expand: Voice over IP calling (for timeline of mobile telephony)

- Wi-Fi calling (for both timelines)- The nature of mobile phone voice and data plans, and how these have evolved over time - Cellular connectivity in underground areas, such as subways (I have some example events in https://timelines.issarice.com/wiki/Timeline_of_Bay_Area_Rapid_Transit - Move to IPv6 - tethering and hotspots created by mobile phones are worth mentioning, maybe in both timelines )