Yet, it is only since the 1960 ’ s ​ — with the introduction of flame - retardant fabric, coupled with a safe and inexpensive system of burning propane used to heat and regulate the air temperature inside the balloon — ​ that ballooning as a pleasure sport has really got off the ground. Close - Up Look
या सुरेख फुग्याचे जवळून निरीक्षण केले असता खाली निमुळत्या झालेल्या रंगीबेरंगी कापडाच्या अनेक पट्ट्या जोडलेल्या आढळतात.