1. What is it?

Injustice is when a person is treated unfairly by society, law or authorities. It includes the blaming, ostracising, imprisonment or execution of an innocent individual.

2. How is it made?

3. Examples in literature

The Scarlet Letter 
by Nathaniel Hawthorne

Excerpt from Chapter 3 ‘The Recognition’:

“You must needs be a stranger in this region, friend,” answered the townsman, looking curiously at the questioner and his savage companion, “else you would surely have heard of Mistress Hester Prynne and her evil doings. She hath raised a great scandal, I promise you, in godly Master Dimmesdale’s church.”
“You say truly,” replied the other; “I am a stranger, and have been a wanderer, sorely against my will. I have met with grievous mishaps by sea and land, and have been long held in bonds among the heathen-folk to the southward; and am now brought hither by this Indian to be redeemed out of my captivity. Will it please you, therefore, to tell me of Hester Prynne’s—have I her name rightly?—of this woman’s offences, and what has brought her to yonder scaffold?”
“Truly, friend; and methinks it must gladden your heart, after your troubles and sojourn in the wilderness,” said the townsman, “to find yourself at length in a land where iniquity is searched out and punished in the sight of rulers and people, as here in our godly New England. Yonder woman, Sir, you must know, was the wife of a certain learned man, English by birth, but who had long ago dwelt in Amsterdam, whence some good time agone he was minded to cross over and cast in his lot with us of the Massachusetts. To this purpose he sent his wife before him, remaining himself to look after some necessary affairs. Marry, good Sir, in some two years, or less, that the woman has been a dweller here in Boston, no tidings have come of this learned gentleman, Master Prynne; and his young wife, look you, being left to her own misguidance -“
“Ah!—aha!—I conceive you,” said the stranger with a bitter smile. “So learned a man as you speak of should have learned this too in his books. And who, by your favour, Sir, may be the father of yonder babe—it is some three or four months old, I should judge—which Mistress Prynne is holding in her arms?”
“Of a truth, friend, that matter remaineth a riddle; and the Daniel who shall expound it is yet a-wanting,” answered the townsman. “Madame Hester absolutely refuseth to speak, and the magistrates have laid their heads together in vain. Peradventure the guilty one stands looking on at this sad spectacle, unknown of man, and forgetting that God sees him.”
“The learned man,” observed the stranger with another smile, “should come himself to look into the mystery.”
“It behoves him well if he be still in life,” responded the townsman. “Now, good Sir, our Massachusetts magistracy, bethinking themselves that this woman is youthful and fair, and doubtless was strongly tempted to her fall, and that, moreover, as is most likely, her husband may be at the bottom of the sea, they have not been bold to put in force the extremity of our righteous law against her. The penalty thereof is death. But in their great mercy and tenderness of heart they have doomed Mistress Prynne to stand only a space of three hours on the platform of the pillory, and then and thereafter, for the remainder of her natural life to wear a mark of shame upon her bosom.”
“A wise sentence,” remarked the stranger, gravely, bowing his head. “Thus she will be a living sermon against sin, until the ignominious letter be engraved upon her tombstone. It irks me, nevertheless, that the partner of her iniquity should not at least, stand on the scaffold by her side. But he will be known—he will be known!—he will be known!”

To Kill a Mockingbird 
by Harper Lee

Excerpt from Chapter 21:

Dill was sound asleep, his head on Jem’s shoulder, and Jem was quiet. “Ain’t it a long time?” I asked him.
“Sure is, Scout,” he said happily.
“Well, from the way you put it, it’d just take five minutes.”
Jem raised his eyebrows. “There are things you don’t understand,” he said, and I was too weary to argue.
But I must have been reasonably awake, or I would not have received the impression that was creeping into me. It was not unlike one I had last winter, and I shivered, though the night was hot. The feeling grew until the atmosphere in the courtroom was exactly the same as a cold February morning, when the mockingbirds were still, and the carpenters had stopped hammering on Miss Maudie’s new house, and every wood door in the neighborhood was shut as tight as the doors of the Radley Place. A deserted, waiting, empty street, and the courtroom was packed with people. A steaming summer night was no different from a winter morning. Mr. Heck Tate, who had entered the courtroom and was talking to Atticus, might have been wearing his high boots and lumber jacket. Atticus had stopped his tranquil journey and had put his foot onto the bottom rung of a chair; as he listened to what Mr. Tate was saying, he ran his hand slowly up and down his thigh. I expected Mr. Tate to say any minute, “Take him, Mr. Finch…”
But Mr. Tate said, “This court will come to order,” in a voice that rang with authority, and the heads below us jerked up. Mr. Tate left the room and returned with Tom Robinson. He steered Tom to his place beside Atticus, and stood there. Judge Taylor had roused himself to sudden alertness and was sitting up straight, looking at the empty jury box.
What happened after that had a dreamlike quality: in a dream I saw the jury return, moving like underwater swimmers, and Judge Taylor’s voice came from far away and was tiny. I saw something only a lawyer’s child could be expected to see, could be expected to watch for, and it was like watching Atticus walk into the street, raise a rifle to his shoulder and pull the trigger, but watching all the time knowing that the gun was empty.
A jury never looks at a defendant it has convicted, and when this jury came in, not one of them looked at Tom Robinson. The foreman handed a piece of paper to Mr. Tate who handed it to the clerk who handed it to the judge…
I shut my eyes. Judge Taylor was polling the jury: “Guilty… guilty… guilty… guilty…” I peeked at Jem: his hands were white from gripping the balcony rail, and his shoulders jerked as if each “guilty” was a separate stab between them.
Judge Taylor was saying something. His gavel was in his fist, but he wasn’t using it. Dimly, I saw Atticus pushing papers from the table into his briefcase. He snapped it shut, went to the court reporter and said something, nodded to Mr. Gilmer, and then went to Tom Robinson and whispered something to him. Atticus put his hand on Tom’s shoulder as he whispered. Atticus took his coat off the back of his chair and pulled it over his shoulder. Then he left the courtroom, but not by his usual exit. He must have wanted to go home the short way, because he walked quickly down the middle aisle toward the south exit. I followed the top of his head as he made his way to the door. He did not look up.