Why can't I use Indian rupee symbol (₹) with Arial font? I wanted to use Indian rupee symbol (₹) with Arial font, in TextEdit on macOS Mojave.

However, whenever I select the text which includes that symbol and change the font to Arial in the dropdown, rupee sign font changes to PingFang SC font and the remaining text changes to Arial.

Can someone explain this behaviour?
This is because macOS Mojave uses Arial version 5.01.2x, which includes the following list of characters:

! " # $ % &amp; &amp;#x27; ( ) * + , - . / 0 1 2 3 4 5 6 7 8 9 : ; &lt; = &gt; ? @ A B C D E F G
H I J K L M N O P Q R S T U V W X Y Z [ ] ^ _ ` a b c d e f g h i j k l
m n o p q r s t u v w x y z { | } ~   ¡ ¢ £ ¤ ¥ ¦ § ¨ © ª « ¬ ­ ® ¯ ° ± ² ³ ´
µ ¶ · ¸ ¹ º » ¼ ½ ¾ ¿ À Á Â Ã Ä Å Æ Ç È É Ê Ë Ì Í Î Ï Ð Ñ Ò Ó Ô Õ Ö × Ø Ù Ú Û
Ü Ý Þ ß à á â ã ä å æ ç è é ê ë ì í î ï ð ñ ò ó ô õ ö ÷ ø ù ú û ü ý þ ÿ


Indian rupee sign is not on this list, so TextEdit uses PingFang SC, which is a system fallback font introduced in OS X 10.11 El Capitan:


  OS X 10.11, aka El Capitan, comes with a new system font for Chinese users, named PingFang, it includes 6 weights for both Simplified and Traditional Chinese. The same font also appear on iOS 9 as the default UI font, though Apple didn't mention it explicitly.


No single font contains every possible character.  To see which ones a particular font does have, go to Applications > Font Book, select the font, and do View > Repertoire.  To see which fonts do have the rupee symbol, open the Character Viewer (Edit > Emoji &amp; Symbols), select the character, and look at the Font Variation pane.