Celsius Network partnered up with GEM to provide in-app coin purchases. Currently, there are two crypto providers supported: Wyre and Coinify. Here is the availability of their services:
Africa: Kenya, Nigeria, South Africa
Asia: Hong Kong, India, Indonesia, Philippines, Turkey
Europe: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Greenland, Hungary, Iceland, Ireland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Monaco, Netherlands, Norway, Poland, Portugal, Romania, Russia, San Marino, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey, United Kingdom
North America: United States (Excluding AL, AR, CO, CT, FL, GA, HI, LA, NH, OR, VT, VA, WA), Canada
Oceania: Australia, New Zealand
South America: Argentina, Brazil, Chile, Colombia, Peru
Here is a list of fiat currencies you can use to buy crypto in the GEM section of the app:
List of fiat currencies you can buy crypto with when using ACH Transfer (powered by Coinify):
U.S. Dollar
Australian Dollar 
British Pound U.S. Dollar
Euro 
Canadian Dollar
List of fiat currencies you can buy crypto with when using SEPA Transfer (powered by Coinify):
Euro British Pound 
Danish Krone Canadian Dollar 
Swiss Franc U.S. Dollar 
Norwegian Krone 
Swedish Krona
List of fiat currencies you can use when buying with a debit/credit card (powered by Coinify):
Russian Ruble Euro Swiss Franc British Pound U.S. Dollar 
Brazilian Real Danish Krone 
Czech Koruna 
Romanian Leu
New Zealand Dollar Australian Dollar 
Hungarian Forint 
Hong Kong Dollar 
Bulgarian Lev 
Turkish Lira
Indian Rupee Norwegian Krone 
Indonesian Rupiah
Croatian Kuna 
Philippine Peso 
Malaysian Ringgit
South African Rand 
Japanese Yen Canadian Dollar
Polish Złoty 
Icelandic Króna Swedish Krona
Chilean Peso 
Colombian Peso 
Argentine Peso
Peruvian Sol 
Kenyan Shilling