AS Per IS:1554(Part1)&7098(Part1)

'A' - Alluminium
'2X' - XLPE Insulation
'F' - Steel Strip Armour
'y' - PVC Insulation
'W' - Steel Round Wire Armour
'y' - PVC Outer Sheeth
'ww' - Steel Double round wire armour
'yy' - Steel Double Strip Armour
'Wa' - Non Magnetic round wire armour
'Fa' - Non Magnetic flat strip armour

AYFY Means Alluminum PVC Insulated Fltat strip armour and 
PVC outer sheeth cable

AS Per IS:1554(Part1)&7098(Part1)
AYFY
A-Aluminium
Y-inner shealth for insulation
F- Flat armoured(There is one more thing WOUND ARMOURED)
Y-outer shealth of insulation.
In general practice
 Cable sizes upto to 3CX10 Sq.mm Wound armoured is 
acceptable.( Wound armoured will provide a good mechanical 
strength than Flat armoured)
Cable are selected with FLAT ARMOURED is mainly because of 
finacial reasons and some phical resons in errection and 
maintance